Ideas to make grooming less stressful for older kitty?

Hey guys! Got a question from someone recently, and I'm not sure what to offer them. Any ideas??

Here's the situation:

"My cat is probably 20 years old and is hyperthyroid. She takes medication, and the dose seems about right. I feed her cooked chicken and give her as much dry food as she wants. (Professional Chicken and Rice Formula).
She barely grooms herself, and has matted fur so I try to groom her. Sometimes she's angry though I am very gentle and use the same comb the vet uses. When I scratch her head or pet her on the top of her head and back she purrs. I've thought of giving her a heavy dose of medication and grooming her as she sleeps. Do you have any other ideas. "

So, I ask you guys this: is there anything this lady can put in her kitty's fur to make the process easier? I would like to give her SOME sort of idea, so she doesn't think she has to over-medicate her cat just to groom her. (Am I insane for thinking that's not good for her kitty?)

Any ideas??? Thanks, guys!!

Maybe try a slicker brush instead of a comb, and don't make it so much about "grooming" as it is about spending time with your kitty. Maybe the comb is pulling her hair and it hurts, the slicker brush might be more gentle.

Is there anything that can be added to the fur that would help tangles to loosen a bit and wouldn't be bad for her kitty to groom off later on?

I use a zoom groom on my cat every day. He loves it. But I am thinking it probably wouldnt get out any mats. Maybe if the cat is that bad she should take the kitty to the groomer? They have ways of doing it. I know the cat is old, but....

If kitty has matts in her fur, they are causing her discomfort. Tugging at them with a comb only makes it more painful. They will probably have to be cut out. Have the vet do this if her coat is in really bad shape.
I think too that if certain vitamins or minerals are absent in her diet it will show up in a rough coat. Older cats have special needs, it might be time to change her diet.
Misty used to hate the comb, so I bought a wide toothed brush just for him and paid extra attention to the 'fun' spots, like behind the ears and under the chin until he got used to it. The hard metal combs the vets use are the most efficient, but not all cats will tolerate them once you get home. I wouldn't advise putting any de-tangling product on a cat, even one that doesn't groom himself. They generally don't work, from my experience, and just trap dirt and body oils.

I've got a good friend who SHAVES her cat with an electric shaver. She's being doing this though since he was a young kitten. I wouldnt recommend this to you, but it shows there's more than one way to groom a cat!

Hmm...good ideas, guys! I think I'll ask her if taking her kitty to the vet would be easier for everyone involved. Thanks!