Toni Nadal was not in Auger-Aliassime's box for his match between him and Rafael Nadal and he revealed the reason why.
Toni Nadal had a deal with Felix Auger-Aliassime of not being present in his box if he ever faced Rafael Nadal and he revealed that after the match. He said:
“I had a deal with Felix in which I wouldn’t sit in his box in the case he faced Rafa. He knew I wanted Rafa to win and didn’t even go to his last practices before that match. If he didn’t accept that, I would stop coaching him right away, but he is a good kid”
As you can see in the quote he also wanted Nadal to win showcasing his loyalty to his family which Auger-Aliassime understood. Rafael Nadal hinted at something like that in his press conference before the match explaining that he doesn't think Toni Nadal would want him to lose. He was right.