I thought coaching was not allowed during competition?

While we don’t know what was discussed Brad Angelo and Tom Baker were shown talking during a commercial break and by the hand gestures I would guess Baker was giving advice on how to play the lanes.

It also appeared to me that a ball rep was down helping between matches. Since that was not during a game it might be allowed.

Coaching is allowed between rounds of a tournament. The ruling is that each game on the show is a different round of the tournament. So as long as the coaching doesn't take place during the game it is ok.

The rules in question are.

20.15 Coaching. Coaching is defined as, but not limited to, any
advice given to a competitor regarding ball selection, lane strategy,
mental thought processes or physical mechanics.

20.15.1 Restrictions. Coaching is not permitted until a competitor is
finished bowling for score during a qualifying or match play round.
During televised portions of the event, one game is considered one
round of competition.