I imagine they don't brush their cat at all. But, hopefully they'll do it a bit now after I tell her that it will help.
They won't feed an expensive food. It is "just a cat" afterall.
Honestly, this doesn't sound promising.
Hairballs are most often the result of a poor quality diet and lack of care overall. So I'm not surprised that this cat is suffereing from them badly.
Many things that we cat owners shrug off as "normal" are infact not normal in the least, but the first signs of poor health caused by poor quality food. You see, foods full of fillers, low quality proteins, etc, are going to cause poor health in the skin and coat (since they're barely nourishing the body, the coat's getting pretty much nothing), meaning the cat is shedding in access to what it should, and is consuming more hair when it grooms itself. Causing hairballs.
If they have this attitude towards their cat, it's not going to be any better plain and simple. They can put a bandaid on it in the form of a hairball remedy, but that's not actually adressing the issue.