Trace, I've not been around boats really for that long, so I don't profess to know a great deal about what is a good boat and what isn't, but when I started looking and asking for information advice I was given plenty. Mostly, don't buy a boat full stop...., then don't buy a multi, make sure it's got this, and that etc. Had I listened to all the negative advice, I'd have never had the joy I've experienced for the last two years, even though there have been some interesting times as well.
It was the same when I took up surfing not so long ago, I was put off by a lot of long time surfers trying to tell me I was too old, or not tough enough. When in fact, these people were big noting themselves by telling me how "hard" it was. They also didn't like the fact there was going to be one more "kook" in the line up. In fact, surfing is not hard at all, but you do need to be fit and you do need to make your own decisions from all the crap information you get. Each different surf shop I went into told me to buy what they had in the rack, or what looked good under my arm. Had I believed them I'd have given up surfing altogether because I would have had a board that I couldn't ride.
I HAVE been around motorcycles for 40 years, and often get asked "what should I get?" My answer is the same every time. Go to every bike shop you can find and sit on every bike. THEN have a good hard think about what you want to do with the bike, THEN go and sit on some more and take some for a ride. Each time the list will narrow until finally a bike will buy you. No, there is no typo, the bike will buy you.
It was the same when I bought my wee Top Hat. It wasn't my ideal boat, but money was the major factor. I looked at LOTS of boats on the interwebnetthingy and went to see those that I liked the look of. I sailed some of them and our little Dulcamara bought us. My wife, even though she loves sailing, was against it, but it was ultimately she who gave the final nod. When doing the rounds of the brokers etc, they'd advertise a cheap boat, but ultimately steer you towards what had been in stock for too long.
So, your friend may like the look of Multis now, which is great. Once he's had a look at a nice mono, that might speak to him as well, or he might just like the idea of a multi full stop.
Best advice I could give is for him to take all the advice, sift through how the advice suits his particular needs based on what he knows and subsequently learns, what his gut tells him and if it's more than a passing whim, he'll end up with a great boat for his budget and needs.
There is nothing wrong with giving advice, so long as all the advice given is done freely and without prejudice to one's own preference. As in, just because one wouldn't own a mono, doesn't mean it's not the perfect choice for another.
Or, as my Grandad used to say, treat advice like your penis. You don't go waving it about un-invited in public, you only get it out when invited by someone you care about.

Michael