Breaking lease due to lost income

hi there, first of all, thanks so much for sharing such great content! We're in a position where we had to break lease due to the fact we lost our business/ income to covid last year. there is only one month unaccounted before landlord found new tenant but he is trying to go after us for this months rent (we also moved because the whole house started growing mould!). He is sending us lawyers letters to recoup this amount. Where can i find these new laws that says tenants are protected and allowed to break lease in extreme situations, such as losing their income? We're new residents of Portugal and the lease is here in Portugal.

thanks so much in advance, Samantha