You forgot to set the washing machine to "Whites"

Yea my brother has ruined 2 pairs of airpods in the washing machine.

I wonder what the difference is? One (admittedly uninformed) hypothesis is that there might have been more detergent, and the failure was caused by detergent residue. If this was true, they could be (possibly) repaired by rinsing with fresh water to remove said residue and leaving to dry. (Lots of other possible hypotheses and confounding factors)