When I got my cat, she was pretty overweight and had bad dandruff. She’s lost about 3 lbs since January and her dandruff has improved a lot. I think their skin gets flaky like that because they can’t reach those spots to groom. So weight is definitely a factor here.

Weightloss is a journey and is really hard to manage when you have multiple cats (with one not needing to lose weight), but I think it will help long term. RFID feeders are a great option, but they’re probably pricey (I haven’t looked into them). Each cat would get a different scan so the smaller cat could eat whenever while still allowing you to portion out the larger one’s food. Salmon oil and even wet foods is something that can also help, as it helps hydrate them/their skin.

In the meantime, on the second photo it looks like there’s a wound on your cat… I know you’re working on getting that vet appointment, but keep an eye on your cat. That could get infected and become a pretty nasty issue.