Relying on emergency services only wastes soooooo much money. Waiting until problems are acute and they HAVE to be treated under EMTALA means doing way more expensive treatments and clogs up emergency services. Not to mention that not vaccinating or treating bacterial infections results in a bunch of cooties getting spread around the community. And when they're getting those emergency services they can't pay for them so the cost has to get absorbed into the bills of the patients who can pay either directly or through insurance.
"I don't wanna pay for other people's Healthcare!"
You already are, just in the least efficient and most expensive way possible.
Water aerobics and yoga are usually the best options. I would try to find a yoga instructor skilled in physical therapy / disability modifications to the poses. Water aerobics is typically specifically designed for physical rehab so you're more likely to find most of those classes are geared towards that. If affordability is a problem you may find that your health insurance, even or possibly even especially if it's public health insurance. In the gym though you want anything that's low impact and low intensity like maybe an elliptical on the very lowest resistance setting.