Details of the uniform will probably be more useful, and doubtless those answers will be forthcoming. However, I will mention as a lighting designer that your cousin's theory does have some legs. There appear to be at least four distinct focused light sources, at least one of them from a high angle and several from a low angle, as well as quite a bit of fill light. While not probative, this is not an arrangement that commonly appears in photography or real life, but would not be unusual for stage theatre.

If it is a theatrical context (and I'll note that I'm working off of essentially a thumbnail image here) the setup used for this photo would include several soft-focused lights on stands, probably fresnels (or perhaps footlights), at least one ellipsoidal spotlight or perhaps a fresnel from the ceiling, and probably a scoop or similar providing the fill and lighting the backdrop. Most of this suggests a 30s-60s context. Low-angled light started to become unpopular starting in the mid-30s, due to theories of lighting like those of Stanley McCandless. By the 60s it was almost entirely unused except in the most constrained circumstances. Scoops and other broad fill lighting also became less popular over time, mostly disappearing in the 80s in favor of more ellipsoidal spotlights.

While there could be groups even today that might create a look like this (I could dig all this equipment up from the basement of a local theatre), it's most likely sometime in the 50s or perhaps 60s, possibly in the 70s in a community theatre context, though the photo being in black and white suggests an earlier date.