Is it possible to just hand over the account to someone else or like your son?
This is possible and nobody would know about that, but I would prefer keeping accounts personal and private.
There are some stuff you can give to your children and family members, like Bitcoin, money, house and car, but not email and forum accounts.
Problem would be bigger if I was the owner and creator of forum.
I think keeping one's forum account personal and private is much better, than handing it over to someone else. If it is the password or pass key to wallet addresses, trading exchange, bank account details, withdrawal pins etc can be passed on to the next of kin, but when it comes to discussion forum, no way. The actual owner of the account has created a legacy there, be the account a very active one, not active or only shows in and out. When there becomes anomalies in a particular account from it's actual activities, there could be some reactions from admin of the forum.
Imagine an account that gives supports to those who needs it, or provide some special skills that is favourable to the forum, and because the person has given away the account, we start seeing something totally different from what the account is known for. The legacy of the account will be broken. IMO.