Marvel does a bunch of licensing for pre existing games to release marvel reskins, so if you know a few games he likes, maybe see if any of those exist.

If going away from marvel isn’t a deal breaker, king of tokyo is a great game that has a colorful, marvely, comic book aesthetic. It’s also a great entry level game for a family that may not be seasoned board gamers, but with enough interaction and randomness that you won’t get bored once you get the gist, and nobody can really outskill anyone else.

There is a counterpart game, king of new york, that gets even closer to the marvel theme but the community mostly agrees that Tokyo is the better game because it’s more simple and streamlined vs new York which adds a tad more complexity. NY does have it’s fans though and your step dad might appreciate it more if he’s a huge marvel guy