Advice on improving transfers from bed to chair to commode?

My mother has been suffering from Muscular Dystrophy for most of her life. Now at 70 years old, many of her muscles are extremely weak, and she has trouble being transferred between her bed, scooter, and commode. We’ve had several home aides over the past couple years who are trained to manage these, but they eventually develop back pains from the lifting and transferring. Does anyone have any specific devices or techniques to recommend that might make transfers easier for someone with very little ability to help hold themselves up? Thanks so much!