Long time lurker, first time poster. I couldn't resist the temptation anymore.
I am not convinced his family thought this out and used him as a bait. Rather, he constantly hears people talk about easy riches in wealthy paradise (Western Europe, USA, Canada), where people swim in money, live in nice homes, drive cars and wear nice clothes. He's working an underpaid, menial job in Doha and someone probably taught him that he could pick up desperate, ugly, older women online. That they'd marry him, bring him over, pamper him, take care of him financially, dress him, feed him etc. That he'd only need to be married for a short time, will get his green card and divorce (perhaps even get property and money after his divorce). He then would be able to marry a nice Tunisian girl (him living in the United States ups his chances to marry a nice girl). I'm sure his family did not object, I'm sure they applauded him. But I don't believe they orchestrated it all.
I'm sure Mo feels frustrated. It is very different than his friend told him it would be. He expected luxuries and financial stability, a sugar mama. He got none of that. He's pissed about that. But I do not for a second doubt he is not committed to his green card! He probably erroneously assumed he'd get permanent residency right after marriage. Oops! Not going to happen. Two years conditional and then they will need to apply for removal of conditions.
Even for his first, conditional, green card he needs to prove the bona fide of his marriage. Good luck with that Mo!