Aiming to keep his medical knowledge from rusting, profit was never his concern. Some patients are so poor that they have to wait until they have enough money before they go to see the doctor. Some only go on pay day. Others must borrow money. That's why I always tell my patients to come promptly when they're sick and never mind about the money.
Health comes first.
They can pay later. His sympathy for his patients derives from his own turbulent childhood. I was a sickly child. From my own experiences, I know that getting proper treatment in time is often a matter of life or death. It may be a little shabby, but the clinic is still popular.