I have been trying with my wife, she is on board, but has not found something that works for her yet. I have started thinking of buying new stuff for her as satisfying my shinyitis, every device I buy her becomes my new backup (unless she loses it, I still miss my evod)
Have patience, make the information available but certainly don't push. If you seem to be trying to make the choice for him you will sour him on the whole idea.
The vaping journey is unique for each of us, and what worked for you will not work for everyone. Use what you know about him, his tastes and habits. If he isn't someone who likes to tinker, don't hand him a mech with a dripper on it. Choose flavors he is likely to enjoy, and put your own tastes out the window. I have a massive sweet tooth, so dessert vapes all the way. My wife likes menthol, won't even try any of the sweet flavors that I like. Don't give up, but keep your expectations low. This is not, and never can be, your decision. Just be supportive, and give only the help that is welcome. When he is ready to switch he will, until then keep the door open. Good luck with it.