My husband has mobility problems and one well meaning friend arsehole suggested to me that if he lost a bit of weight he might not need the stick. I just stood staring at them, then said I had to go. Really what I wanted to say was "gosh, why didn't I think of that? I'll just tell him to come off the 35 tablets and six sachets a day he's on (many of them cause weight gain) and he'll lose that weight. Of course he'll be in screaming agony and be dead within a short time as the cancer will kill him, but sure he'll be a lovely thin corpse!"
I'm sick of people suggesting his mobility difficulties have to do with his weight. The best about it is, they only say it to me, which is a good job as I'll rip their fucking heads off if I hear them suggest it to him. 
Why do they assume they have the right to give an opinion or 'advice' about some one else's mobility or disability?
Obviously when he's having a bad day and using the wheelchair it's cause he's one of those 'fat, lazy people' 
that just can't be bothered to walk.