Player unintentionally copying?

So I'm posting this because one of the players in my game was a little late to the party in making a backstory. They've been there from the start but have only now gotten a backstory to the DM.

It takes heavy inspiration from myself and the other player. Maybe not intentionally but a similar family story, losing a person of the same relation to their character, a similar tragedy that kind of stuff. (Not exact just giving examples)

All a few sessions after we shared ours.

( I don't know the full backstory but the DM has checked in with me if I'm comfy with what similarities I know.)

I am not entirely comfy with this but I feel like an AH if I say to make them change it. Because they could have mentioned this when we were talking and it would have been ok coincidence. Instead they added it AFTER.

It feels bad but so does asking them to be original with theirs.

What should we do?