For many artists, it's a simple part-time job and then comms on the weekend.

I consider it a part time gig, since the work is not steady, and I don't make nearly enough to even make rent on the best of days.

I'm not an artist, but I've seen some artists really thrive by expanding the mediums in which their works can be enjoyed. Stick with the stickers, but consider the pretty meteoric rise of acrylic standees, art prints, print-to-order tees (I think this is a good possibility for you!), and the fact that pretty much all of these can be done on a distributor contract basis. Little bit of copyright dodging may be in order (Megaman? No that's Blue Shootguy!), but I can't imagine any outfit worth their salt wouldn't have familiarity there.

Send out inquiries and start those processes now, and shift your focus to more pressing issues. I'm sorry you're going through this harrowing time, be sure to be there for your loved ones.

I have not seen many artists that can support themselves on their art alone, and AI is only making the situation worse for everyone. The ones that can are already super popular and people are paying them almost like $1000 per commission or something ridiculous like that, so that is out the window unless you are already super popular with rabid fans.

The things that I have seen people try that makes them a bit extra money is doing something like drawing their commissions on live stream, so they can get the ad revenue from that, as well as putting up the video on youtube later for long term money. Selling merch of their art or characters (stickers, posters, plushies, etc.) since those can keep getting made on an assembly line after you draw them just once. Some of their try making a video game Etc.

Most people use art as the side hustle, meaning their have a main job doing something else, and the art work is where they get their extra money.

Meanwhile, if you already have a nest egg built up, you can look into having a retirement firm invest it for you.