HI S.,
6 1/2 months old seems a little old for Swaddling. When you mentioned that he's rolling over, my first thought was, his hands are tied up! I have three children, I would never leave them unable to use their arms once they could roll over.
I think it's time to wean him from this. Start at nap time, that's when i would start. Put him down for a nap, with a blanket on top of him... tuck it in on the sides, that might help. you'll have to let him fuss, he might even scream, but he'll sleep after a while.
Once he realizes he can sleep without the swaddling your life will be easier. Also, he may sleep better on his tummy. I have a 9 month old daughter whos been rolling over since 11 weeks old, she's slept on her belly ever since. Once they can rollover you'll find them on their tummy a lot more often. He may rollover and feel "swaddled" or more secure on his belly.
You'll never know until you give it a try.