Respectfully - I think that's terrible advice.
Because: GUE Fundamentals will give someone both nitrox and dry suit training. It even says so on the card. It also includes doubles training if you chose to aim for a tech pass.
You are also encouraging someone to take a GUE course (which includes the philosophy of their diving) and then go and ignore the whole ethos and do a solo diving course.
Respectfully, I find your objections ridiculous. I chose to take the GUE fundamentals course in parts in order to have the time to practice and assimilate as many of the skills and as much of the information from part 1 as possible before taking part 2. I've only completed part 1, and it was an intro to GUE philosophy, gear configuration, and lots of skills/drills practice, which is exactly what I wanted and expected. Since I have yet to take part 2, I really don't know for certain everything that will or will not be covered. I didn't know about the nitrox component in part 2, so thank you for adding that information. I had no idea a Fundies card included a nitrox cert. On the other hand, if I don't wear a drysuit or bring doubles for part 2, I'm not exactly sure how much useful training in that equipment I'll be receiving, and since that describes my circumstances, I'll be wanting future drysuit and doubles training sometime afterwards.
I chose to take GUE fundamentals in parts and recommended it that way because of recommendations and the perceived practicality. I do not know of a better course for an already certified OW/AOW diver to take to expand his knowledge base and improve his diving fundamentals. This is in addition to the introduction to GUE. However, I don't claim to know about every course out there.
I've always been told "you don't know what you don't know," so I think it's more reasonable for a diver to make an informed decision about the adoption and implementation of GUE diving principles AFTER having some direct GUE experience and training. You don't really expect a diver to potentially discard much of what he has learned and experienced and 100% adopt the entire GUE philosophy solely because he has signed up for a training class, do you? That certainly appears to be your expectation based upon your post.
I'm also very aware that GUE teaches unified team diving. I'm also aware of the FACTS that each person is ultimately responsible for himself and not everybody is fortunate to have a GUE dive buddy for every single dive opportunity. As such, I think the SDI solo course is a great way for a diver to learn what they don't know about solo diving - situations, equipment, philosophy, etc... Taking a solo course does not guarantee that a diver will become a solo diver just like taking GUE fundies does not guarantee every student will become a GUE diver; however, I do think that every diver would be a better diver for having taken and learned from both courses. They both provide an opportunity to be exposed to and learn about things they may not have known. If you don't approve, that's not my problem. It's only my 2psi which is worth about as much as was paid for it.
Anyhow, best wishes and safe diving for the op on his diving journey.