As a parent of two college students, I have to say I don't regret helping my kids out. In fact, I don't want them to have much debt when they get out and am glad to do it. We are blessed that they do get lots of financial aid, though. We still have to pay for housing, incidentals, clothing, etc.

If your dad didn't want to do it, then I think he would say he couldn't. I can understand wanting to feel guilty, but I don't think it's necessary. Just remember down the road that your dad might need some help (financial or otherwise) and if you can, then it would be nice to help him some.