That’s why Nintendo wants to serve his family members cause they probably know he’s at one of them…and once he’s been served they’re responsible to send it to him or else they will be held accountable

That's not true. Nintendo wants to serve to family members because they (officially) haven't been able to get through to him yet, and his family members may be able to contact him where Nintendo has not been able to.

I also doubt the family members have any legal requirement to serve the papers to him. That would be a bit ridiculous. Imagine if some lawyer could hand you random court summons and now you're legally required to find this person and serve the papers. You may say that it's not the same situation because they're related, but at what point are you related enough to a person where you can have this legal duty thrust upon you, especially given how most people have family members they're not in direct contact with? He's not criminally wanted; they wouldn't be hiding a fugitive or whatever if they refuse to serve (assuming they even know where he is, which it's perfectly plausible they don't).

In any case, it shouldn't really matter. The streamer has demonstrated publicly that he's aware of the lawsuit and at some point that will probably be deemed sufficient notice, possibly for the case to continue in his absence if he continues to be unresponsive.

Wait, serving a legal notice can be made transitive to people not part of the legal system?

Like, I could just sue someone the other end of the country and then arrange things so that the notice is delegated to my landlord if (small if) they're being a jerk?