I can't seem to find an etymology that traces the root of φιλέω, φίλος, φίλιος back to Indo European, but something occurred to me recently and I'd like to know if it's plausible or already known to be false or what.
The 3 aforementioned words have various meanings including "friend", "friendly", "dear", "to like", "to love", and interestingly also "to kiss". A related noun φίλημα even means "a kiss". This was the key that made it click in my mind; years ago in one PIE resource that I found online a root *b(h)u(s)- was listed with the meaning "lip, kiss". I wish I could find a cite for this one, as it doesn't turn up in any of the usual lists of roots that I check with, and can't think of any words that definitely derive from it.
But perhaps it was the zero grade form of a root *bhwes- which could have had the suffixed forms *bhwes-lo- and *bhwes-lyo-. These would likely have derived to φίλος and φίλιος, respectively. Notice how the latter parallels the hypothetical *gheslo-
, which in its suffixed form may have been the root of χίλιοι.
Is it reasonable to assume that *bhw- would have derived to φ- in this way, and might the verb form φιλέω be explained via the stative -ē- suffix?