I would say it really depends on how much you care about him, and if you're willing to bear the weight of some nearly inevitible psychological guilt, so let me explain.
Consider how shook up he seems to be after the divorce with your mom, even though it's years later. A psychologically healthy human being would have moved on, but he seems to have fallen deeper into the mire that has become his life. It really sounds like to call him emotionally unstable would be a gross understatement. If he has rallied whatever will he has inside him to admit his mistakes and reached out to you, you could very well be his last hope. And it is also not unreasnoble to assume that rejection by his own child could very possibly drive him over the deep end.
Needless to say, this puts you in a very unfair position, but unfortunately life is quite frequently unfair. You must choose to either forgive him, potentially being the force which can bring his life in a more positive direction. Or you can choose to reject him, potentially speeding his life in the negative direction in which it seems to have been headed.
So I would say that the right thing to do would be to forgive him, and try to help him. The benefits are that you might be able to change the life of someone who cares about you. To choose the other option, while it would be understandable, will result in negative changes in his life, and if you are a normal sympathetic human being, will also probably cause you a considerable amount of guilt. I would say the benefits of forgiveness far outweigh the potential consequences of punishing him with rejection for his past relationship with you and your family.
Consider how shook up he seems to be after the divorce with your mom, even though it's years later. A psychologically healthy human being would have moved on, but he seems to have fallen deeper into the mire that has become his life. It really sounds like to call him emotionally unstable would be a gross understatement. If he has rallied whatever will he has inside him to admit his mistakes and reached out to you, you could very well be his last hope. And it is also not unreasnoble to assume that rejection by his own child could very possibly drive him over the deep end.
Needless to say, this puts you in a very unfair position, but unfortunately life is quite frequently unfair. You must choose to either forgive him, potentially being the force which can bring his life in a more positive direction. Or you can choose to reject him, potentially speeding his life in the negative direction in which it seems to have been headed.
So I would say that the right thing to do would be to forgive him, and try to help him. The benefits are that you might be able to change the life of someone who cares about you. To choose the other option, while it would be understandable, will result in negative changes in his life, and if you are a normal sympathetic human being, will also probably cause you a considerable amount of guilt. I would say the benefits of forgiveness far outweigh the potential consequences of punishing him with rejection for his past relationship with you and your family.