Undesired Family Member Nanny

Has anyone had their SO want to use a family member as the nanny that you did NOT trust one bit? It is so wrong for so many reasons and he is still pushing the idea and talking to his family member after I explicitly said “not now”.

Our daughter spent 2 weeks in the NICU and was discharged with a NG tube. It’s not easy.

I try to give his niece the benefit of the doubt, but she is the epitome of whom you do NOT want caring for your kid, much less a NICU baby. She can’t hold down a job to save her life, she lies like its her job, she’s unreliable, do I really need to go on?

How do I get out of this potential nightmare???