Someone with PWS needs a manager diet. They are more at risk of obesity, they gain weight much easier. Yes they have irresistible hungry, I remember once documentary which featured a family that had loved the kitchen off so their little girl who has PWS started eating the cat litter, those with PWS nearly always also has Pica. I don't understand why Harvey isn't under a dietitian and on a strict meal plan!
Treadmill issue, the house does have one but nearly all treadmills will not be suitable for Harvey as they have a cut of limit of 15-18st, ones which are suitable for him costs thousands. Also because Harvey has been in residential care his PIP would have been stopped, I'm not sure how it would work with him being back home due to lockdown however.
I would love Harvey to get suitable exercise equipment and become healthier so if Katie was a genuine loving parent I wouldn't see an issue with it however we all know it's for Cole really.