I'm unsure as to how old you are..but maybe you just haven't learned yet: boyfriends never get the point. That's their job.
O.K. kidding to lighten the mood.
But seriously...2 things: 1, if he did "get it", he'd both be very afraid for you, as well as have to do something drastic and dramatic, like possibly have you hospitalized. He has no idea how to approach this, likely, and obviously doesn't want to have to do something like that against your will...if necessary, turning you against him--so he's stuck between a rock and a hard place ...and so he "misdirects" by going off on something concrete, as a material and practical problem he CAN turn his man-mind, problem solving orientation towards, and address successfully. Cars and removal of them as the practical solution to ensuring your safety.
He's trying to help you, in our practical guy way....he's just scared sh8tless, and has no idea where to start. But he knows he needs to make a big deal out of trying to keep you safe, to let you know he cares, so he's putting that all into cars...exactly the kind of matter-of-fact hands on approach you could expect from a guy, and a "vehicle" to communicate his concern for you--to you--especially when he knows he has to be seen "solving it" some how...but he has no idea where to start.
2. He likely doesn't want your relationship to "round that corner". You're in essence demanding he change his conception of you, as the girl he's in a particular flavor of relationship with...he's thinking of you as someone he respects and as a "viable member of average society"...and you're essentially putting him on notice that--no, in fact you're not that girl after all...now you're revealing yourself to be "someone else" entirely , someone who doesn't fit those qualifications in his likely "normie" un-PTSD oriented mind (which is common enough, and not his fault at all). So he has no idea how to relate to this newly qualified you. Alien territory.
If he in fact accepts that you are universally unconcerned with the prospect of your own death, in any form, his only realistic reaction can be a genuine and honest "holy sh8t" moment...and a forced game-plan change, that he neither has any idea how to approach or address, including a "changed you" which he'll no longer really be certain how to relate to on this new level. So he's doing what humans do...he's resisting that by staying in denial of it...by giving the slip to the point you've aimed in his direction.
He's not getting the point...because he doesn't WANT the point. That's my take on it anyway. Don't know him or you, obviously, but I can easily see it playing out that way.
. he cant understand its not what I'm doing or what I'm holding its my state of mind.
MAYBE you should ask yourself a few questions, first: Why are you telling him this, really? I mean, I know it's natural for anyone to want their loved one to know what their reality is like, what it's like on the inside of their head. But maybe you need to make that explicit to him, to make clear that that, alone, is your intention and motivation. Because remember, when a guy hears his girl say anything like "I've got a problem"....bingo....flashes up on his screen as "It's my duty to solve this, as her Man". And how could he be expected to "solve" that? It's really putting him in a bind, after all, isn't it? Guys don't work well on a "just understand it" level. They pretty much see things in terms of "problem? solve it!" level.
So maybe if you take a quiet moment, at the right place, at the right time, and frame it properly with an appropriate lead-up, so that by the time you launch the actual hard-subject matter, you've put it in context....then he'll be able to hear you...because he'll understand that that's all you want...to be heard, not "solved". It'll take the pressure off. He won't feel as much as though he's been tossed a nuclear hot potato, and expected to make french fries out of it.
How do I make him understand, I've tried freaking him out and saying bluntly I don't care if I live of die but he keeps going on about the car. I'm getting really frustrated with him. He's trying to help but just doesn't understand.
He doesn't want to hear that you don't care if you live or die! Would you want to hear that about someone you love?
I mean, I really think you should stop and think for a moment: Are you, in fact, legitimately suicidal? Because that's what someone being told what you're saying is going to infer. And do you know what loved one's do when they hear that, and really believe that? They lock you up, for your own good--that's what. And they should.
So maybe you need to divine your own motivations for telling him that. If you're just having feelings related to ennui, and existential angst, and the meaninglessness of life...maybe you should be talking about it to a therapist...or at least making that clear when you broach the subject, so it doesn't sound as though you're making suicide threats.
So you're seeing his "going on about the car" as just not understanding...when in fact he's seeing it as his not being able to afford to understand...if he did...he'd have to lock you up. He'd have to totally change his conception of you as someone so unstable that at any given moment in the future, you might suicide, and not be around anymore.
I think it's just a matter of you and he missing each other in going opposite directions. He doesn't understand that what you're telling him is that you're suffering from a kind of philosophical crisis, the realization that you lack motivation towards life in general....
And he's likely hearing..."I'm about to kill myself"...and his mind is going "HOLY SH*T!!! Maybe if I just ignore this for as long as possible, it'll go away, and be like we never brought it up! PLEASE PLEASE PLEASE!"
So maybe write him a letter about it. That feels right--you won't even be there for him to feel as though he has to react immediately for your benefit (guys do this, by the way)...so he'll be able to get through the whole thing and digest all the subtleties before he feels he has to snap into reaction to it.
But if you really are suicidal, please see someone urgently. There are local community clinics, where low cost psych related consultations are often pro-rated, especially in emergencies. But I'm glad you're posting here for support and resonance. I've definitely spent some time in that place myself, so I understand the distinction between "I just don't care about life", and "I'm about to kill myself". I do understand the difference, and most here would, I think. But the average person--probably has a difficult time separating the two...especially when it's a boyfriend who rightfully feels as though it's freak-outable material, in his girlfriend.
All the best, be well, and hope you'll continue to post for support.