I'm sorry, but your post really pisses me off and annoys me, because it's clear that you have absolutely no understanding of either Algerian culture or Islam - yet, thought it was a good idea to marry someone, and have a child with, someone who calls himself Algerian and Muslim. Intercultural and interreligious marriages are hard enough to cope with separately compared to monocultural and religious marriages, but combined they're even more challenging and hard. They are not for everyone, but they're mostly not for submissive people like yourself who are not informed enough to ensure that they'll not be treated unfairly. Sorry to be blunt, but it's the truth. You need a lot of education/information, moxy and spine to cope with intercultural and interreligious marriages.
I'm looking for people who are married to Algerian men or who understand that culture...
What you're describing is not "Algerian culture" - you're describing a very dysfunctional man and his clearly even more dysfunctional family that have completely unreasonable expectations of you, and are treating you like dirt. Because you're not from their culture, lack information about their culture and religion, and because you seem completely unable to enforce boundaries, they're sweeping the floor with you, then walking all over you. They know you'll allow them to.
...I'm Christian and Muslim so I think we had very fundamental difference ideas on responsibility
You clearly don't know even the basics of Islam. Or probably even your own religion, to be honest.
I'm a practicing Muslim, and I can tell you that it's an Islamic law that a man must financially support his wife and children. No ifs or buts about it, bringing in the money and spending it on his wife and children is a Muslim man's godly duty. It's not a choice he can opt out of. Islam places great responsibility on a man's shoulder to look after his family, both financially, emotionally and spiritually. Men are considered the leader of their household who must ensure that their family is loved, supported, guided and looked after in every way.
Your husband isn't doing what he's Islamically duty-bound to do, and his family are, from a true Islamic perspective, oppressing you and being unjust to you. They're absolutely in the wrong, and we Muslims do not claim this outrageous behaviour as part of our law or moral compass.
If your husband and his family respond to Islamic reasoning - which I suspect they do not - you really need to educate yourself on the religion and learn what your rights are as a woman. And then actually claim them, and remind your husband and his family what their place is.
Your husband's duty is firstly to you and your children. But your husband has chosen to be a substitute husband to his brother's wife instead, neglecting his own actual wife and kids. It's a really grave sin, and neglect is a really valid reason for divorce.
Also, please don't help this man become a citizen, either. How disgusting that your husband's ambition is to leach off the state and let taxpayers fund you all - again, completely out of line with Islamic teachings and values. You really need to ask yourself is this marriage and man bring anything good to your life...