I don't really know how old this question is, but I'll answer it anyway! I believe that Josh is part Indian(not a native american) and part English. I think so because I have seen a video in which both his parents appeared. I have also googled his last name and I found out that Madin without 'e' means delightful:)
He might be Indian, even though he has hazel greenish eyes. Some Indians can be born that way. (Isn't that cool?) Or, maybe a mix of Indian and something else? Hope that helped a little maybe? :)
... And I just want to say this too--> Madan means God Of Love! Perhaps he should consider a last name change;)