~snip
To OP, i don't know where you and that father lives. But depending on where you live, not reporting someone you know committing crime may cause legal trouble. Have you and him consider taking next action?
Exactly what I thought.
A Cex seizing someone's asset, when they have important information shows that the person must have done something that might have warrant such action, and might even place the person on their radar. And maybe one of the victim might have made the report in this case. It is definitely a tough decision to make at this point considering the fact that OP is related to them, and the father won't want his son to be in any sort of trouble. But like you said, there might be some legal troubles, especially if Bybit decides to handle the case seriously.