This could make for an uncomfortable family reunion.

An adviser working for the hedge-fund manager who sued the New York Islanders for reneging on a deal to sell him the team is NHL Commissioner Gary Bettman’s half-brother, The Post has learned.

Andrew Barroway hired Jeffrey Pollack several months ago after reaching a handshake deal to buy the club from owner Charles Wang for $420 million, sources said.

Wang and Bettman are believed to be pals.

Barroway also hired David Carlock, a sports-marketing specialist, as a late addition to help in his Islanders bid — which ran into trouble, sources said, when the Philadelphia lawyer and hedge-fund executive had trouble raising the money needed for the purchase.

Barroway says he had the funds.

Wang in mid-July unexpectedly raised his asking price for the team from $420 million to $548 million, making it nearly impossible for Barroway to complete the purchase, the lawsuit claims.