Nah, don't believe him. Some refs from that time already came out and admitted to being pressured to ref favourably to Barca:
Thanks to Andújar Oliver, a ref of the same period, we also know that Negreira´s son would call the refs in charge of the important games that happened in Camp Nou. He would ask them at which hotel they were staying and then would drive them personally to the stadium. He admits that, he being the refs VP son, he could not turn him down.
Yesterday, we learnt how on one of this trips, where Negreira´s son was driving the 4 refs (referee, two assistant referees and the fourth referee) to the game at Camp Nou he told them:
“You know: here, calm down. Barcelona has a lot at stake and you can´t hesitate. You are more than prepared. You know exactly what you have to do."
Video of Negreira's son accompanying refs to Camp Nou
It is worth remembering that, while doing all these, Negreira´s son admits being employed as an external consultant by Barca (as per his CV available on the net). It is worth remembering that he, and his father, got paid 7M€ by Barca during 18 years.