Emi

This is what I would do, unless your friend is already fediverse knowledgeable. If you have knowledge about what subreddit they enjoyed the most you can use the community browser to find what instance has the largest similar community and show them that. https://browse.feddit.de

It makes sense from their perspective but still kinda shitty.

The real question I think is will Reddit retaliate back and forcibly recover communities and install new mods?