Probably was brother in law but at one time also controlled three gyms of his own.
After being an unsuccessful bodybuilding competitor he turned to weight lifting and became personal trainer to several showbiz personalities.
Although best known in Star Wars as Darth Vader he was also the Green Cross Man for kids' road safety (with no slippage in his tights):
https://www.darthvader-starwars.com/...k-training.jpg
http://www.youtube.com/watch?v=CRUBMBi_lp4