Names are a dime a dozen!
If he's been using it before you, it would make sense to find a new name...
It's not the name anyway it's the music!
If your music is signed, different and better and you make a go with your stuff and he doesn't than why give him a coat tail to hang on to!
If he's making a go of it, then people will think your coat tailing
Either way I would change it!
It's the kind of thing that gets a write up in your bio when your famous!
"Bubba BlockerZ changed his name back in 2010 because of another artist who had been using that name previously in 2008. BBZ went on to 10 successful platinum records after changing his name and never looked back...."
BTW....You can use "BBZ" if you want! Hehe...
Just look me up someday after you've gone platinum as BBZ and maybe give me a little credit on the suggestion! 8)