A friend of mine was telling me he was hungry and so I said he should get food. He then said "but you're not here to get it me". At this point I told him that it didn't sound like an actual correct sentence but he argued it was. I tried to tell him how weird it sounded but he just said that since he's the British one and I'm Swedish, he'd know the language better than me. So is it actually a legit working sentence or not?
This construction is, I think, restricted to British English (and possibly British-derived Englishes—I don't know what Ozzies and other colonials say). I can't remember ever hearing it (or the parallel Give it me) in the US; we'd say "You're not here to get it for me".
What's involved here is actually a collision between two 'rules'.
The first is that a semantic Recipient cast as a nominal indirect object rather than as the oblique of a preposition is supposed to lie between the verb and the semantic Received, the direct object—it's that sequence that informs the hearer/reader which nominal is the indirect object and which the direct object.
Get/give Joe a sandwich, not *Get/give a sandwich Joe.
The second is that the 'new information' in the construction should occupy the last, stressed place in the clause. Consequently, if it is the Recipient which is the new information, it will follow the Received and be cast as the oblique of the appropriate preposition.
Get a sandwich for Joe (not Sam).
Give the sandwich to Joe (not Sam).
But in your example, neither the Recipient nor the Received is new information—not only in this particular context but virtually by definition, since both are expressed as pronouns—and neither should occupy the stressed position.
So whaddaya do?
If you're American, you might just say Gimme (or, more minatorily, Give); but that's usually too peremptory for civil conversation. So we compromise: we use the oblique construction, but emphasize the verb and put secondary stress on the preposition, which de-stresses both pronouns.
You're not here to get it for me.
But BrE speakers have the option of employing the object construction, with no emphasis on either pronoun: everything falls away from the verb.
Get me it. or
Get it me
If it makes you feel any better, it sounds just as odd to me as to you; but us foreigners don't get a vote.