Guys a little guidance here. My new colleague has just started flying with me and he has some jet time and lots of single engine time. While we were departing an airport recently we levelled off at 8000 ft. You could see the ground and lot's of pop corn CB's all around with tops reaching 12-14000FT. He was adamant about avoiding all the clouds as he says they posed a threat to our safety, I disagreed and he turned whiter than a ghost. He absolutely thought we were going to die. He has done the same thing whilst on a sid just getting ready to join the approach. Mind you, I am not talking about Thunderstorms, no lightning clouds are white in color, but a couple do paint red on the radar, however the tops are visually sighted and not higher than 14,000.
Any ideas, advisory circulars, information that I can look up to assuage this guy, or, am I the one that needs retraining. I'm open minded and thick skinned so I can take constructive criticis
m. I would not fly into anything I feel would be dangerous and that would start to be developing CBs with tops above FL200. Any help would be appreciated.