Not to resurrect an old thread, but if this didn't get resolved, I might have some input...
Oooh, the food waste might be telling. When my boyfriend and I were trying to figure out what he was, one of the things we discussed was how he connected everything in his mind and he gave the example of how he will not waste food, and if he has to, he feels very guilty. He thinks about garbage he produces filling landfills, and tries to comfort himself with the thought that the food items will be eaten or broken down by other animals, but it still bothers him.
He's also not sports-oriented whatsoever. I don't know if he ever really has been. He's much more into looking at and making art (much more the former than the latter). He's been doing some very good art since he was 14 or so, and although he's amazing at things like lighting, angles, perspective and proportion, he has a difficult time with minute details.
As a child, he spent hours alone or with a couple friends fantasizing. Is that something your daughter's boyfriend did?
In almost all situations, my boyfriend is quiet and reserved and doesn't really 'put himself out there'. That could just be a difference it development and parents, though, since his are more-or-less unfit as guardians and very critical, judgmental people.
He's very 'dreamy' and self-critical. He's also high strung and very anxious. He says he has a difficult time connecting to people. He seems to loathe coldness and cold judgments, which is a problem when I transform into my INTJ lycanthrope self for the winter.
Although he and I have argued about it for a while, he swears up and down he's INFP, very strongly. He even went over the Ni/Ne Si/Se, etc., and found that he fit the Ne, which, he says, makes him seem more 'sensate'. I would have to agree he has a lot in common with INFPs and less with ISFPs.
Not sure if that helps. I know very few, if any, SPs (or SJs, for that matter) because I generally only get along with Ns of any sort, so I can't really pit him against Sensates in practice.