Re passive monitors: depends on whether he wants something purely designed for mixing or for listening pleasure as well. Yamaha NS10 is kind of the industry standard for passive monitors Not sure what would fit the bill if he wants to mix and enjoy listening for pleasure.
I've had a succession of active monitors over the years, Tannoy Reveals, Adam Ax5 and Genelecs. I'm currently using my stereo set up with the 70s Celestions, and honestly for what I do (mainly acoustic based songwriting stuff) it's as good any anything I've had before.
But i'm aware that's just my taste for that gentle, transparent almost squishy feel without super accentuated high or lows. Plus i'm no longer mixing very often, or realistically expecting to match commercial releases for fidelity. My tastes are what they are, I like imperfections and character and all the music I do these days is strictly for my own enjoyment of the process.