my dad got a bonnie back when I was in highschool and that thing only sat for a year or 2 and we needed to replace pretty much every fuel line and I believe a lot of a/c lines as well. instead of messing with the a/c we just drove without it obviously we changed the fuel lines but just put it into perspective this car did sit outside so maybe that 2 years is like 15 years inside lol. but if you would like to go at it I would just start with the tube and seals and see if that can fix the leak. the compressor may still be good. the only way you can test the compressor is if the system is full as it has a sensor that will keep it turned off to protect it. you could try to get a second opinion and see if they can pinpoint the leak. but this mechanic is not taking the wrong steps because for him to pinpoint it by replacing parts refilling it and emptying it each time odds are you will be paying way more in labor than if he just did it all at once plus some parts could go bad In the future
