I have a BHFEA520j stick sweeper that the bar stopped turning and was actually stuck. Hair had incurred in between the inside of the end cap at the end opposite the drive motor. This cap has a square end that locks into place to keep the roller in place.
The hair that had gotten into that area had actually melted and this friction welded the cap to the roller.
There are two choices depending on willingness and time available. The entire roller can be replaced along with the bearing cap. The second choice is to try to remove the end bearing cap from the roller brush. In my case, a leather hammer facilitated this. The surfaces that meet from brush to cap will have to be scraped of burnt melted hair taking care to preserve the features, especially inside the bearing cap. Mate together and roll to determine smooth operation, tiny squirt of WD40 and you should be in business.