you can call that chord Bm/E, but it´s clearer to treat the lowest note as the root. So what we have here is a
E7sus2
there is no third (G or G#) involved, so it can be a replacement für a E minor or a E major chord.
in detail:
E = root
B = fifth
F# = major second → sus2
D = minor seventh
^Exactly! 
The key words in my response were ‘in context’. I assumed you had this chord progression recorded. A 10 second snippet would’ve sufficed. I don’t need a snippet to know how that chord sounds, but I’d need it to know what
chords preceded it, what the duration of the chord was(was it a passing chord), and what vocal melody, if any, was on top of it. You said you and your friend are in disagreement about whether it works or not. We’d need to hear it -in context- to decide whether it works, and either agree with you that it works, or with your friend that it does not.
I remember seeing his name on here, glad to hear he’s ok.
Bm7 over an E bass is a voicing for an E Sus chord…
I would call it a 9 chord not a sus2 chord… sus 2 means the 2 is next to the root. Just my upbringing. E9.
sorry, that is wrong 
E9 means E79, a dominant seventh chord with a added ninth - something totally different from the example here
sus2 means the sencond replaces the third, no matter in which octave - that´s the case here!
Em add9 would need a minor third, G
E add9 would need a major thirs G#
Well in this case there is a 7 and a 9 - just the third is missing. If a G above root E were included, I’m sure you’d agree it was a minor 9 chord. Anyway, no arguing here, we know what it sounds like!
the safest way is to view the lowest note of a chord as the root. In the end that´s how he hear it!
and then there are slash chords like D/G, D major with a G in the bass.
You use those Chords to outline a movment in the bass, e.g.
Am - Am/G# - Am/G - Am/F# - Fmay7 → chromatic bassline, think “Michelle” by the Beatles
The octave, in which a note occors doesn´t play such a big role. the 2nd becomes a 9th and the 6th becomes a 13 because of the nature how chords are built, by stacking thirds on top of each other. So a 9 can appear next to the root, and the 2nd of a sus2 chords can appear in the top voice.
I have to add the there´s no strickt rule how to name chords. I´ve seen so many different chord symbols, many of them appeard wrong to me in theory, but in the end they “did their job” in outlining a harmony.
A 2nd is called a second when there is no 7th. If there is a 7th included you call the 2nd a 9th. Same rule for both dominant and minor 7th. Same thinking for 6th > 13 as r.u.sirius pointed out.
The way chords are built and the way the overtone series works has some common ground. You build from the lowest note and up. This works so well in so many cases you just have to accept it. Don’t let that keep you from adding low notes or extend chords downwards, though! 
Just realize it’s an exception, call it whatever sense to you or anybody involved and move on.