This is slash and burn politics.
I read up on attorney/client privilege and the courts are very reluctant to use attorney’s statements against their clients.
https://www.americanbar.org/groups/business_law/publications/blt/2016/07/12_borrasso/
I think the only reason we are seeing any statements or rumors about Cohen is because Mueller knows he can’t use him as a witness or evidence. So they are just leaking information for Democrat red meat. Any lawyer worth anything would have all Cohen statements, records etc. thrown out and also barred from the witness stand. Cohen is all Mueller has which means he has nothing.