Thank you guys so much for your help and your kindness :hug: :hug:
I'm sorry I haven't updated on this yet. A lot has happened in the past week, but bottom line is that I'm feeling much better.
A few days ago I had one of those deep conversations with my dad. The kind that I really hate but that are also very important. I expressed to my dad how incredibly worried I was about him. At first he tried to laugh it off and make jokes about it, but I didn't let him get off that easily. I made sure to keep the conversation focused on the fact that I fear he might decide to commit suicide. He eventually did tell me that he had been very depressed before (I remember those days, they were horrible), but he had no intention to ever kill himself. It was obvious he did not like talking about his current feelings, so to be sure my message got through, I made him promise me to never do such a thing. To never leave me behind like that. And he did promise me.
We hugged and I cried. I do feel like a huge weight has fallen off my shoulders. However, I will keep an eye on him. I know how good he is at pretending to be fine and all the tricks he uses to convince people of how happy and cheerful he is. I use a lot of those very same tricks.
@Anarchy thank you for the suggestion for DBT. It does sound like something that might help him. One thing I did read about it is that part of it is group therapy. That may be a problem. If there's anything my dad hates more than opening up to a therapist, it's opening up to a T plus a room full of strangers x)
I have come up with the idea to write my dad a letter for father's day, containing loads of happy memories and things I love about him. I don't want it to be too strongly related to me being worried about him, though. I want him to know that I love spending time with him and that I don't just do that in order to keep an eye on him.