Lamar, 36, who was in a relationship with Jenner's daughter Khloe Kardashian, was in the news recently for reportedly boarding a flight in drunken state, reported Aceshowbiz.
"I don't know what happened. It was a big surprise to me. All I can say is I just want the very best for him because he's like my son.
"He's a part of my family and I adore him. He's the best. He's the best! He's the greatest guy in the world and anybody that knows him will tell you the same thing," Jenner, 60, said.