One thing she might want to be cautious of - in a lot of businesses, employees sign a non-competition document that prevents them from working independently for any clients of their current workplace for 12 months (or whatever it may be) after either they quit / are terminated OR the client ends their contract.
That may not be the case but if it is, signing it means the worker agreed to pay some hefty monetary compensation to the company for the loss of the client / business. Some people will do it anyway and take their chances but your mum may want to be aware of that if she hasn't talked with her favourite person yet.
Hope it works out for everyone!