I am sorry to hear about this concern.
I hate to say it, but the easiest solution to really help would be getting her professional groomed and having a lion trim performed. Shave down the coat will help greatly with the hairballs as well. Please, do not attempt to shave her at home.
Also, I am a huge fan of essential fatty acid supplements.
I prefer the veterinary products, which are already dosed for pets. Your vet
should carry a product on their shelf, or over-the-internet you can look for Aller G3, 3V caps, EFA-z, or Derm caps.
Also, here's a great supplement to help with hair balls. The link is only one example, you can buy at lots of places.
Lastly, at this age, definitely consider a basic blood profile(with a thyroid level) for an overall health assessment. Also, there may be some source of dental disease or systemic (internal) problem causing the appetite issues. The vet can also prescribe appetite stimulants.