If he is older than advertised, the problem isn't about his character - not for me at least. It's that he's a man competing against boys, for the most part, and you have to discount his numbers when you evaluate. I've said it before - there are a bunch of guys in the G-League who would look like stars if they were allowed to go back right now and compete against college boys. Pretty much every season, there are a couple of guys in college who came to basketball late. And the scouting reports always say some flavor of this: "...but he will have to expand his reportoire to succeed at the next level." And I try to watch those guys. Rarely ever do they actually expand their reportoire and become significant at the next level. Remember Bismack Biyombo, and how crazy most people were about his "upside" before the draft? Biyombo is probably Tsiebwe's ceiling in the NBA.
I commented on Tshiebwe a day or two ago, and said that I would really like to see him succeed and get paid. But there are several other big bruisers that will probably be available that have more game, and I think are more likely improve before they're too old for it to matter. Is he a good guy? Sure seems to be. If I came from the Congo, would I lie about my age to try and get paid an NBA salary? No question about it, I would. And I hope he does. But I think the Spurs can do better in this draft.