Come right out. Did this proceedure on my 356C following the instructions in the best VW mechanic book ever - Muir's "Idiots guide to keeping your VW alive forever". Best $21 you or he can spend -
https://www.amazon.com/Keep-Volkswagen-Alive-Step-Step/dp/1566913101
IIRC a 3 arm puller is needed (been 15 years since I did it) and you will need to confirm voltage coming out of voltage regulator and tweak if needed.
(and for the purists who dropped their jaws when I said I used a VW book on a 356, I do use Elfrink's for the actual measurements - the Idiot's guide is rather well named for me, and it has wonderful "how to do it" directions. I just ignore the numbers and look up the right ones)