My opinion on this is do whatever feels right emotionally, if you don't have to fake emotions and feel truly happy cheering for a team for specific reasons then do it.

6 teams is really pushing it far beyond the limit though, especially 6 teams from the same tournament.

But at the same time only supporting one nation because others tell you to is bullocks either, do whatever feels right.

I, for one, have three nations I could ever truly cheer for and be immensely happy when they win without faking any emotions, and before starting to hate obviously I have a back story for this.

Austria, since I was born and raised in Austria (as simple as that)

Iraq, because my parents are from Iraq and the part of my family that isn't Austrian are Iraqis, so I guess that's not hard to understand too.

Number three is a bit more "exotic" if you will. I mentioned it on this sub several times though and mainly got positive responses. Number three is Portugal, and no I'm not Portuguese in the slightest but that has a very long backstory. It's mainly because my other two nations were barely ever in a world cup/euros and in my childhood that didn't bother me at all, because my favourite players were all Portuguese, I adore Portugal as a football nation.

Since Austria and Iraq would never clash with Portugal up until 2016 this was never a problem for me, I cheered with Portugal like they were my own nation, I still feel true emotions when they play, I guess it just carried over from cheering and idolizing Portugal for basically my whole life.

Seeing Austria clash with Portugal was a dream come true for me, it was no problem at all actually. I really enjoyed that Austria were in the competition for once and facing Portugal was a absolute dream.

In the end, honestly who gives a fuck. Let everyone support whoever they want, if there's no legitimate reasoning behind it like your friend and his "ancestry", they won't feel true emotions supporting their 6 nations and only enjoy tournaments half as much as we do.