My initial take on Marc is that he is good for Brad right now. He also lost someone in the 9.11 tragedy and is a loyal person and a great lay. I think Brad can really appreciate someone like that in his life now. However, like I said in my review of the latest chapter, I can't see Brad settling into the role of sugar daddy for the long haul. Brad has always surrounded himself with people who push the envelope and Marc doesn't come across as very challenging.
I think the family will be happy to see Brad happy and probably will give them plenty of latitude. However, they are all protective of Brad too and if Marc becomes a problem for Brad, like asking Brad to choose between him or Brad's family, then Marc will be gone. Of course Mr Arbour probably has something entirely different in mind, but the name of the book is Streak and like all streaks, I foresee this one as coming to an end at some point. Just, sayin'!