One of my kitties is an overgroomer. She first started licking and chewing herself raw when I got her fixed. She went to town on her shaved tummy and had to wear an e-collar until the fur grew back. Then she started on her paws. There's no obvious environmental or food trigger, but the thing that helped alleviate it the most--beyond cortizone shots as needed--was a companion. Since getting my other cat, Henry 9 years ago, she's only had two or three flareups, and with a long-acting cortizone shot and an e-collar, I was unable to get them under control rather quickly. I think she just gets bored and lonely.
Good luck. It' s a tough situation. If they have a vet they've worked with in the past--especially if the know about Lore--then perhaps they'll give a discount for any necessary treatment.
Live with intention. Walk to the edge. Listen hard. Practice wellness. Play with abandon. Laugh. Choose with no regret. Continue to learn. Appreciate your friends. Do what you love. Live as if this is all there is.
--Mary Anne Radmacher