Yet again because it's a stepson it's not his fault the dad needs to do more, what if his dad is bending over backwards and his still behaving like this if the OP hadn't written stepson the answers would have been different if a woman was posting on here that her child had said her dh wasn’t a proper father people would be questioning just how involved this man was in his child’s life actually.
Haven’t read the other threads (yet) but if this child is thirteen then he is at a point in his life where he feels the world should evolve around him unfortunately it seems that a lot of NRP’s (men usually I’m afraid to say) seem to feel that there rights and those of their partners and new families are more important than their existing children’s.
The school event is a red herring. He didn’t just decide his father isn’t a father based on that one event and neither did you decide that your H has depression because of that one event. There is a bigger picture here, and you simply cannot just decide that the child is entirely to blame.
And it may be that there are two sides to this, i.e. the father is to blame for not putting in the effort and the teenager is, well, a teenager and will have his moments as well, and the two don’t always make for a good combination. But your dh also has some responsibility towards his child here.
Oh, and the wish to tell him that he is the cause of his dad’s depression? Yeah. My eXH’s DP tried to pull that shit when my DS was about the same age.
I suspect that in his case he is torn between a woman who insists that he put her and her children ahead of our DS, and the realisation that DS sees what goes on and has stepped back because of it. They have almost no relationship now and he refuses to stay there because of her.