Would it be good for him to go back to making art?

Do you have Deviantart?

No, but I've been curious to know if something similar to this place exists and if my art could work there.

Dont know any that is still alive, is you have pinups (+18 characters) or no sex stuff you can upload them to DA, I have a premium account so I could b00st some of your works, so much people could see your stuff

Also DA have a fuction for commissions but it have a very high fee (20%) likely will be better do deal direct deals if you ever get a commission offer

So would it be better to try DA? And you say they take a 20% commission on artwork requested through their platform?

Yes you should give it a try and yes, unless you have a premium account, dont premium users have a 20% fee, keep being reduced the highest your premium is, up to 5% is the minimum but wouldnt suggest to buy one unless you feel confident enough you will have enough clients ¯\_(ツ)_/¯

Starting from scratch on a new platform sounds complicated. But I need to make some money from my art and my time. Thanks, friend.