manage to find their way inside the prisons anyway.

I don't know why, but I would suspect that much like jail is here, you need friends/family to bring you certain things in jail (extra food, blankets, etc.) so by staying around she can at least go visit him occasionally, bring him something he might need (though sounds like there's a lot that she needs as well). I doubt she has delusions that they'll just go job hunting again when he gets out.

"Most plain girls are virtuous because of the scarcity of opportunity to be otherwise."
-- Maya Angelou