Nadal is a self-confessed Real Madrid fanatic, though also insists he wants the best for his fellow Spaniard, Yamal.
Asked about the issues engulfing Yamal off the pitch, Nadal told Movistar +: "He should surround himself with people who truly support him and who know how to listen to what many choose to ignore.
"He must have those who sincerely care about him, whether family or staff, and learn to take their advice seriously. It's crucial to keep his feet on the ground and not live in an unrealistic world, especially at his age.
"Success can make you happy, or, if handled poorly, it can consume those who achieve it."
Nadal also joked about his future.
He added: "I'd like to become president of Real Madrid one day. Of course, the club already has an excellent president, Florentino Pérez, and they don't need me, but you never know. It's an exciting project, and it might be a distant, but real, possibility."