I am with LPH on this for all the reasons she stated plus I really want to reiterate that this is much more for your benefit than his. You have every justification to be angry with him for years of rejection and neglect, that is emotionally very difficult to overcome.

A really wise dear person once shared with me the following...forgivness is a gift to us from God, it's not about the person we are forgiving it's about us and for us. The person at whom our anger is directed feels no pain from all from our angst, they don't even know it exists, they go about their life unaware of the damage being wrought. But that pain eats away at our joy in life and robs us of happiness. Forgivness is far too difficult for anyone to do by themselves. Even Jesus could not forgive, He asked His Father to forgive His executioners.

Whether you end up going or not, ask for forgivness for this person, you may be surprised at the results over time.

I am currently in a situation where I have been betrayed by a friend and my anger had no end to it. It's been consuming me, the only relief I have had from this is when I ask that this person be forgiven. It has created a crack in my anger and I hope over time it will dissolve the anger and pain. It's a gift to us that is free for the asking, no person should have to live with anger.

Take care of yourself, stress kills.