just the weight of the vehicle puts a helluva side load on the bearings what makes you think adding discs (which weigh a fraction of drum brakes) would cause bearing failure?
"goes thru wheel bearings" how many did he "go thru"? replaced them once? maybe he bought cheap POS bearings? replaced them more than once? maybe he didnt install them correctly? maybe his axle is bent? there are alot more things I would look at if I had a bearing problem than what you are describing
what kit does your friend have?
