I can sympathize, had the same player you describe last year. This year I got lucky at the draft and have a team I really like!
The only thing I’ve ever found to get any motivation from players like this is always give lots of praise whenever they do something good, no matter how little. And give even less corrective advice, his teammates will take care of that side. However if you hear teammates saying negative things to him nip it (they’ll be plenty you don’t hear).

Good luck,
Steve

Thought I would give you guys a little update, now that a few practices have gone by.

So dad shows up at a practice. Big guy -- really big. Honestly, I am a little worried. Well he gets on his kid pretty good and keeps him moving, hustling, etc. Kid has a good practice. Unfortnately, when dad is not there -- it's back to walking up the court. Going to be an interesting season.