amybe you're all so angry because you've been robbed
of normalcy. I can understand why that would enrage all of you, it's just not fair!
Living in constant stress takes it's toll, and you have to acknowledge that as a family and try to work together to alleviate it. Maybe you could tell your dad about your feelings about his constant pain and the way he expresses it, maybe he could control it a little? Often, when people are in pain they don;t realize how it effects those around them, they are, afterall, the one suffering. Maybe he could do more to appreciate your reaction to it.
People living in these conditions often do best when they take extra good care of themselves, finding creative outlets, being with friends, getting away, surrounding themselves (at least some of the time) with normalcy. Try to do that.