If you were in his shoes, can you declare your crypto asset to your family? Or do you think he should have declared it to them after the extended family members must have left and even if he did, the information can still leak to the extended family and from there it can escalate to other people. What opinion do you have to give in this situation?
I would definitely not be comfortable declaring my assets or holdings in front of anyone who I don't believe. If it's family members that you trust and know that they are of no harm and they only wish for you to have a better life and a good future, then you can declare it to them and show them what you hold so that they can trust you and believe in your words, but I don't see any necessary involvement for extended family in this.
If I was in his shoes, I would refuse as well, and say it clearly that I don't want to declare anything in front of everyone and that I don't feel comfortable. Sometimes in life, you need to be straightforward and say things without hesitation to avoid any sort of problems later on. If you can't stand for yourself, no one will stand for you. It's a life lesson I have learned.