I am so so so sorry to hear that. At least you completed your project before he passed and at least he isn't in pain anymore. We hate to lose loved ones but we don't like to see them suffer either. When my brother passed away (in 1995 to bone cancer) he too withered away and it was so hard to watch it happen. He was 38 years old and we were very close.
Just try to remember the great times you had with him. Take care of yourself. We are here whenever you need us!