Tough luck on your friend, but i can see why they would take it for a typo. I was curious about that name , because I've never heard of an Irish surname beginning "Mick ". And so i googled the name, exactly as spelled by yourself, and best i could find was a handful of instances of it being used as a forename. All apparent instances of Mickinsy as a surname turned out (upon clicking the link) to actually be mis-spellings of McKenzy (for the first few pages , at least, at which point i got thoroughly bored). Also checked McKenzy (and variants)and found that it was invariably spelled Mac or Mc in Ireland , same as in Scotland. Also stumbled across the info. that this surname origininated exclusively in Scotland. Ofc, that's by no means true of all Gaelic names beginning Mac, but it's true of this one. So if it really is a variant of McKenzy, then your mate really does have Scottish ancestry if you go back far enough. The name is common enough in Ireland, but all Irish McKenzy families came rom Scotland originally. ( Also wondered, btw, if it might possibly be a new variant on McInnes/McGuinness? )
I'm now wondering if you mis-spelled your mate's name on this board? I'm also (more to the point) wondering if there's a typo or mis-spelling in pre-existing official records for this guy, with the result that they're just not finding an expected match? Might be worth checking. According to (American) statistics that I found, that name (as you wrote it) is somewhere between extremely rare and unknown (less than 5 instances out of > 6,000, 000 records )
Anyway, my understanding is that Irish are called "Micks" because Michael is a really common Irish forename , though we more often call them "Paddies" here in the UK (cos Patrick /Padraic is an even more common Irish forename) I checked this on Urban Dictionary, and it had , in its most popular definition : "Some beliefs are that "mick" comes from the common "Mc" in many Irish names". But this was from an American perspective. Nobody in Britain would pronounce "Mc 'as "mick" ; We invariably shorten all such Gaelic names to "Mack". Intersting to think that Americanisation might be producing a whole new variant. "Mick..."is certainly not the
Irish spelling of any such name, but might possibly be an emerging Irish- American spelling?
Yeah, i got over-involved in researching this one, spazz that i am
Good luck to your friend.