Recovery after stem cell

My 70 year old father had stem cell transplant 6 weeks ago tomorrow. He is home but struggling. Weak, tired, in bed most of the day. He is being looked after at home by my mum as we are unable to help withCOVID 19. He is visiting hospital once a week where they say he is going great but we are worried and wanting some reassurance that he's recovering ok and that he is doing on this many weeks after the transplant. Any advice is greatly appreciated at this strange time!