In my first few semesters, I could've easily managed a job on top of my schoolwork. It'd have been pretty hectic and I would've had a much harder time settling in and getting accustomed to how assignments, tests and the like worked, and I can't imagine that my GPA would be what it is now.
If I'd known I would need to work during school, I definitely could have taken lighter course loads in order to accommodate for this, but I feel that it'd be impossible for me to add that over the past few semesters. I'm averaging 4-5 hours of sleep, which might not be unusual for some people, but I'm much more used to 8. This is partly because I'm not very good at managing my time well (I think this is partly due to my tendency to walk away from things I'm having a hard time with for a while to let my mind hash it out on the back burner), but mostly because this semester fucking sucks.
I think the thing that's eating up the most time is my AI class. The "problem" is the assignments are completely open-ended and very research oriented. I spend entire days tweaking parameters to my solutions that took less than an hour to create. It's probably the funnest/most rewarding class I've taken here, but holy crap it takes up a lot of time.
Anyway, the bottom line comes down to priorities, I guess. If you want to put your kid's education first, then I think your solution is about as close to optimal as you can come, crazed. Pay for it if they're serious, and tell them to take a hike if they're just going to waste the opportunity.
I've heard some people here say that a "high" GPA is largely irrelevant when it comes to getting a job, but my experience has been exactly opposite of that. Literally every place I've interviewed at has made a positive remark about my GPA. Most of them are to the effect of "You have the kinds of skills and the GPA that we're looking for in an intern", etc. The last thing I'm trying to do here is boast -- I'm merely stressing that it really is important, at least in the internships I've been interested in. In one of the more "lucrative" ones I applied for this time around, I had a guy call me talking about full time positions for after I graduate.
I think some people are excellent at managing their time and could absolutely be self sufficient and take on very difficult course loads. This is probably something that you should take into account before you make the decision.
This is something I could drone on about for a long time, but I think I'll cut myself short here. Good luck with the loans. Unfortunately, I don't have any advice as to where to get the loans. If you really are interested, though, I'm sure I could find plenty of people who can give recommendations.