In my opinion, I don't think you should go look at apartments with him, or even help him on the phone sort thru his options. I understand your concerns about your daughter, but this is just the same kind of "rescuing" behavior that we're trying to get you out of.
You can simply say to him "Great; let me know when you've found something, as I'd just like to see it before you pull the trigger, as D4 will be staying there often, thanks!"
