The low LH theory in relation to erectile function, IMO, doesn't jibe. Exogenous testosterone lowers LH but more men than not have improved erectile function, along with improved libido. As most of us know, at least here in the US, there are thousands or tens of thousands of men on some form of TRT. They're not on forums. Then there are men who aren't on TRT, just taking a PDE5 inhibitor or Trimix or PT-141 or even some form of thyroid replacement. The more sex, the more testosterone production, in part, via increased LH.
Certainly, if a man uses ibuprofen and it improves erectile function and libido, irrespective of the underlying mechanism(s), he should enjoy his improved function and leave the 'why' to research.