Can you stay and continue your job? No. Your permit is tied to his and if he leaves then you either have to leave too or your employer has to apply for a new permit for you under the non-EU hiring rules.

https://www.sem.admin.ch/sem/en/home...zulassung.html

Him/you applying for C permits would be a possible answer. Another is to change his currency of payment from pounds to francs. I assume he's paying most/all of his taxes here so I'm surprised he even bothered to keep being paid in pounds. The exchange rate over the years surely hit hard.