AFAIK...if your friend has completed the flying course while on the UAS (and with c.90 hours I am guessing he has), he should have received proof of completion (I believe some sort of form/certificate), which will allow him to obtain a PPL with little or no flying required.
I'm afraid I don't have time to search myself, but have a look in LASORS...it's all in there.
(Warning...the above is a dim recollection of something I may or may not have seen whilst looking for something else...
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