How to extract and then add new refrigerant oil to a home hvac system after existing oil was contaminated with humidity?
First you will need a new filter dryer. With the copper repaired Pull a high vacuum  below 500um on the system for 24 hours or longer this will remove the moisture. At first you may not be able to get below ~3000um because of the moisture outgassing increases the pressure. Once a good base is achieved keep it there for 24 hours and the moisture will be gone you will also want to do an acid test, if positive you will need to flush the system, I like Qwikshot acid flush. I would probably upgrade to a newer refrigerant that might not cost much more than a recharge since R22 can run 100$ per pound a 5 ton unit the Freon alone could cost you over 1k and you still have an old system.