That was his brother, Donnie. Mark was Marky Mark (and the Funky Bunch).
If to stand pat means to resist evil then, yes, neighbour, we wish to stand pat.
He was part of the group for a short time (a few months?). He was young, maybe 13. Left the group and later formed the Funky Bunch.
shareHe... What? Shush. Pretty sure that was his brother
shareHe actually was in NKOTB for a short period of time but wanted to do his solo thing and left. He reunited with the group back in June 2015 at a concert.
https://youtu.be/6MmVVAHKUc8
He was an original member but didn't like the bubble gum pop type music.
I was one of the many New Kids on The Block fans in the late 80s and 90s.