Hoagies has links to websites for enrichment for all ages and subjects. Here’s their pages for geography and social studies links:
https://www.hoagiesgifted.org/geography.htm
https://www.hoagiesgifted.org/social_studies.htm
Sporcle is a general quiz website with quizzes on everything (not just academic subjects)
https://www.sporcle.com/games/category/geography
FreeRice has quizzes on many subjects, including world geography. Every correct answer donates 10 grains of rice to the UN World Food Programme.
https://freerice.com/categories
You say he doesn’t like to read, but he might like looking at the pictures in National Geographic. I think there’s a kids’ version too, but I don’t have experience with that. Here’s their kid’s website:
https://kids.nationalgeographic.com/
Postcards from Buster was a PBS show. It looks like one season is available on Amazon, but requires an extra subscription.
Where on Earth is Carmen Sandiego (the original cartoon) seems to be free on a number of streaming channels, including The Roku Channel.
It looks like there’s a newer version called Carmen Sandiego on Netflix.
While it’s already taken place this year, I highly recommend you take him to future Smithsonian Folklife Festivals. I haven’t been since COVID, but they slways had kid activities along with live demonstrations, performances, and great food.
https://festival.si.edu/
Sakura Matsuri is a Japanese festival held in the spring. It’s great too.
The Smithsonian Museum of Natural History has some exhibits about cultures around the world.
The National Geographic museum sometimes has exhibits related to other cultures. It looks like they currently have one called Beyond King Tut.
https://www.nationalgeographic.org/tickets/events/event/beyond-king-tut-the-immersive-experience/?utm_source=google&utm_medium=paid-search&utm_campaign=tut-exhibit&utm_term=branded&utm_content=responsive&gclid=EAIaIQobChMI_bvrlaTB-QIV2jizAB1H3gf4EAAYASAAEgKen_D_BwE&gclsrc=aw.ds
I think once you get started, there’s a lot that you and your husband know that can be adapted for a young kid. As the US is an immigrant country, it reflects the history and cultures of the nations they came from. There are immigrant communities that still reflect those. You might try doing a country a month at a time. You could start with Greece - read him Aesop’s fables and read him some myths. If you think it’s appropriate for his age, watch Percy Jackson. There were also some really cheesy old movies made about the myths. Disney made a feature about Hercules. You could read Magic Treehouse Hour of the Olympics or Time Warp Trio My Big Fat Greek Olympics and maybe have some family competitions (or challenge him to see how fast he can run, far he can jump, etc.). Try baklava. Talk about pebble voting and then vote for trivial things with pebbles (checkers, coins, beans, etc.). Talk about how they liked theater and take him to a children’s play. Maybe take a visit to an art museum, but he probably won’t want to linger.
Basically, every culture has folktales (children’s non-fiction section), art, food, traditions, games, theater, music, etc. YouTube is a wonderful source, as he’s already discovered. DC is a fabulous area between museums, festivals, restaurants, embassies, etc. Just do what sounds like fun to you and don’t stress about doing everything. It needs to be fun and easy for you as well as him.