He is entitled to do whatever he wants with his life. And I know many people who live a life cobbling together jobs, housing, and the like that lets them pursue other interests. Paddle bums, ski bums, thru hikers, musicians etc. etc. There is nothing wrong with being a bike bum. But the people I know all work, however minimally to support their endeavors. If your father has cancer, why not get a job, contribute to the household and not worry about your neighbors. In other words be a man. A man who lives at home at 30, but still a man.