So, It was allowed to have multiple accounts with the duplicate tags only no matter how many accounts you have. Did I understand correctly? The accounts with duplicate tags were not allowed to join the bounty campaigns. So, it is fine that he has multiple accounts but the offense is having those accounts without duplicate tags.
Having undeclared multiple accounts was a violation always. Main idea is that it is enough for a person to have only one account.
Did he participate in bounty campaigns with all those accounts? What were his other offenses? I guess karma abuses? What if those accounts do not belong to him but to his other family members, as he mentioned? Should he have the duplicate tags even if those accounts were handled by his family members? Was it mentioned that accounts from the same IP will be considered multiple accounts? Many of us use shared internet. This especially happens when you use cellular data. I never knew who used the IP before me.
You know, there are decencies in Internet. If you have an account for your goldfish and domestic turtle you should behave as if you have a multiple account. So no sending karma, no participating in the same activities, etc. If you don't follow this, no one will ever believe that your pet cat is clever enough to use his own forum account. And if you follow this you can expect others to understand your situation.
As one of the judges of the forum I learned a bit about how the decisions were made and I can say that it is very unlikely to get a negative decision basing just on some coincidence. As for shared Internet: once years ago I found that a person I know and who definitely was from the same internet gateway used the same service as me, and there was strictly forbidden to have multiple accounts, and we were from the same area and used that service for years and nothing bad happened. Because they didn't look at some coincidental information only. Here the same.