Justin registered 10 goals and five assists in the Eredivisie last time out to earn comparisons to his father, who wished to see the 19-year-old remain in his native Netherlands for another 12 months.
A move to Champions League semi-finalists Roma worth just short of £16m now looks certain to go through, however, and Patrick insists that he will support the youngster's decision.
"I personally said to him maybe it's better to stay one more year at Ajax, to make some kilometres to be important for the team," he told reporters ahead of Sunday's Soccer Aid even in aid of UNICEF.
"He's 19 years old. He's still young but he makes his own decisions, and as a dad, I have to stand behind all the decisions that he makes. It looks like he's going to leave Ajax. I think it's 90% sure that he's going away.
"If he's got the feeling to leave then he's got to do that, but he needs to know what things are coming on his way.
"It will be difficult because if you're 19 and you're going to another country, it's not easy. You have to pick wisely what club and also talk really deeply about how his progress will be."
Justin Kluivert has previously opened up on his desire to play in the Premier League, admitting in February that he would like to represent one of Arsenal, Tottenham Hotspur or Manchester United.