Offer your forgiveness to him, first. He may feel guilty for not helping you, and forgiveness might ease some of that pain.<br />
Can you do a joint therapy session with a psychiatrist or counselor, so that you both can be honest and supportive toward each other? If there's a trained, neutral third person, that individual can guide the conversation and help you both to understand how to proceed.<br />
Encourage him once more, but don't push him too hard.
Yes, you should definitely care. He's your father, and you seem to be a good son. :D