P2SH format - starts with 3
An address that starts with "3" could be "assumed Segwit, however, That is not necessarily correct, it could be a multi-sig address(not Segwit), you can't tell unless they spend something from that address.
Of course, given that he is the owner, he probably knows -- but we don't.
For more info,
read this.
** would be better to specify in the OP that addresses must be "Native Segwit, not just segwit.