Medical health issues

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I suffer with RA , Crohns, Renal Failure and as had a stroke. But I've managed to lose over 7stone. Some due to cancer and some due crohn's. But now I'm 10st10lb with little muscle on my bones. I'm 54 and 5"1'. Was 17st 10lb. Trying to build my muscle but I trier easily or my stamina is poor. Wont go to a gym yet. Love to swim, that's the one thing I do but not enough. I eat ok but small portions and only 1400cal due to issues with my esophagus. Yes I'm a medical nightmare. I need idea to tone up my thigs and bat wings. Plus build up my stamina and motivation to do it daily or every other day. I just need pushing .