Steve has already been mentoring Kabongo. Kabongo has commented on how much it means to him and how much it helps.
You just have to look at Steve's own stats to see what kind of improvement is possible. Going from 42% to 53% FG shooting over 10 years. And from 2/1 to 8/1 assist to TO ratio and from .3 pts/min to .5 pt/min in scoring. It wasn't until his third year he even started playing 30 minutes a game. His physical skills haven't improved that much. He was 22 years, 8n months old when he started playing in the NBA. He didn't peak until he had been in the league for 10 years.
I think a guy who has improved his game that much, and maintained it at that high a level has something to teach a younger player. Particularly one who has already said he wants to continue to learn from a veteran.
8/1 assist to turnover ratio? He has the highest turnover ratio of starting pointguards (on hoopdata) and is averaging over 3,5 turnovers a game. An 8/1 assist to turnover ratio would be outerworldly.