This is why it's good not to store all your bitcoin in one wallet. It's better to use two wallets, you keep the large amount in a seperate wallet like a cold storage and keep some amount in your online wallet, so that when such thing happens like this, you can show them your online wallet.
What if he has different wallets and decides to show them the one with little coins inside they will still not be contented with the amount they will see there as they will feel that he has mismanaged his funds.
And so what....let them say whatever they like or are you trying to impress anyone.
It's not advisable to declare all your bitcoin hodlings to anyone by force be it your family members. What of those his brothers that are into physical earnings, did they declare all their asset and funds in the bank to the family?
No one should be pressured to declare their asset to anyone but the brothers and the family were literally concerned that he is not doing well from their own perspective since they haven't seen any physical improvement based on how people feel that when you start making money from your investments, you will now start doing things that will convince them that you are doing well for yourself. And moreover, he has already told them that he's into bitcoin.
Why it's not advisable is that your family members can start pressuring you to sell your bitcoin, especially when there's a huge dip that bitcoin is crashing and if you refuse, they will start calling you a fool and different names. Family members can make you not hodli as longer to your expected timeline, and many can discourage you.
It's better that you follow your heart and carry out a healthy investment practice without anyone telling you what to do or monitoring your bitcoin investment for you.