You might want to find an occupational therapist, or physical therapist in your area to come to your home and provide instruction for the best way to assist Saij without causing yourself harm. I know there are ways of lifting & transferring that work better than others. Just difficult to explain in a text format; except to say never lift using your back, try using your leg muscles to do the bulk of it. I think this means bending your knees slightly to a "standing squat" position with keeping your back straight. Best to get this from a professional though.
When we had a local occupational therapist come to our home he was paid by MDA for the visit. Try to find one who can bill MDA if possible, perhaps somebody your neuro recommends.