Mouldy Audi A4 2008, help needed

Hey guys, I have an issue here. So I bought an A4 a few months back from my mechanic, but the back window was busted, so it obviously allowed mould to be in the car. I’m just wondering, is this salvageable? The reason I bought this is because it was very cheap and my mechanic is going to engine swap it to a better A4 engine with lesser miles on it