ER’s don’t do chemotherapy. Chemo is not an emergency treatment. However there are government programs that will pay for your chemo if you need it - Medicade and Medicare.
Chemo is a long-term treatment. The patient does not enter suspended animation between sessions; so long as they’re alive they can work to earn what they can to pay for it, and the hospital will work out some kind of payment plan and/or discount if the patient just asks nicely and earnestly seeks to work it out.
Heck, I knew a nurse who had a permanently bed-bound patient who dealt dope. Where there’s a will there’s a way.