I think his name was Lance something-or-another?
Lance Kerwin. I remember because I have the People magazine 25 year anniversary issue, and they mentioned a bunch of former child stars.
It was in 1999, but it seems he is living in Perris, CA. He is raising his daughter Savannah, who would be about 8 now, and working with addicts at U-Turn for Christ-which “provides nonmedical rehab and Bible study for addicts.”
He was arrested in '89 for possesion of crack cocaine, but the charges were later dropped.
That was three years ago, I don’t know what he’s doing now, since I’ve only heard of him from this article.
They also mention the kid from Mr. Belvedere, and let me tell you, he is really cute now!
Wow!
I used to love that show when I was little.
Dammit, they all turn to crack 
You can use the Internet Movie Database to answer any question like this. Here’s the page on him:
http://us.imdb.com/Name?Kerwin,+Lance
Click on the Biography link for his life story.
Holy Crap!
He was in a bunch of other stuff besides James at 15!
Whoda thunk it!
Lance Kerwin is right up there with Chris Atkins as far as bit parts and a downward spiral to his career track (wait, was there ever an upward spiral?)