Hello, my mother house was built in the 1950’s and the plumbing under her shower is leaking and has a hole. I would like to cut out the bad parts and replace with pvc. I’m not sure what I would use to thread into the top threaded part which appears to me to be brass (although I’m not experienced in plumbing). I have read that it’s not good to use a female pvc adapter to thread into metal. I will attach pictures which shows the leak. Any advice would be appreciated, thank you.