It sounds like your friend has a decent team, which has resulted in the following

1. The league above his (6) was short of teams and has called upon lower level teams (like your mates) to fill in
2. Because of this (I presume) his scout list will show world class players, as he's a level lower than his league level. I maybe wrong here, I've not had this happen to me so I can't say for certain
3. As he probably has a decent team, he plays against higher opposition. Nord bases the cup on your best 14 players, which can lead to you playing against higher levels.
4. Same as one, he's jumped a league because of a shortfall.