I don't think PTSD makes a good excuse for neglecting someone.I also don't think the shoe doesn't work for everyone for every trigger, it can take a lot to overcome PTSD learning in the brain for someone and that much energy can wear me out in a day. Where as for another trigger, one can overcome it easily. It just depends on how scared of the trigger she is.
I just spent an hour hugging my son who was asleep, because although I pretended to be their for him all day, my heart was off in a distant land of my mother telling me I was responsible for self destruction in the family and then doing her abandonment and I don't love you anymore to get you to do what I want routine. I nearly made someone melt at a shop who told me my son's pram wouldn't fit in the shop when it clearly did. I felt like she didn't want bub damaging her stuff. I didn't want to be close to anyone today, just wanted to try to stop the steam coming off.. And then I feel like I love bub again and I can be emotionally available, not just pretending to be when I remember the pain of my mother's insincere love after the trauma. I feel like love is ripped from my arms when I can't love or be close to anyone. I wont' talk to my mother again for this insincere love trip straight after I was attacked by the person who gave me PTSD. It's not all a bed of roses on the side of not loving either. I sometimes treat my husband like he is a sacrifise, that there is only one person I can love in the world( my mum chose someone to always miss out on the love) I can't help it, and pretend not for it to be like this. but it is (yes I am guilty). But I did know love that was sincere once, and it was from friends when I was 19, and I am trying all I can get back to that. I am slowly getting there, able to love again, more and more. I don't think my PTSD is PTSD sometimes, I think it's a broken heart.
You can heal a broken heart but it takes time and patience, and a professional.