[tluyben2]

I have been in this situation (I was burnt out and knew it) as CTO (and co founder) and suggested to my right hand to replace me and find something better for me.

I personally think you should discuss it with him, maybe first over a drink in a more casual setting figuring out how he will give up his role (to you for instance) and what he will do after, leaving his ego intact while putting the company first. He can then suggest it himself publicly and be done with it.

[headscientist]

I'm torn on this. It's possible he would be very receptive and appreciate the frank conversation. It's also possible he will wonder where I get the gall to suggest to him, in however a constructive or trying-to-help way, that maybe he doesn't actually want to be CTO anymore and should consider giving up his role. He's not the type to freak out on me or anything like that, but it could sour the good relationship we have.