Sure, your students may very well spend the little free time they have learning maths.

But are any of them going to be able to do any significant amount of studying maths without being homeless?

your students are crazy (neutral term); no one should learn maths if the condition is that they will be homeless and exposed to the elements. the will to subvert the hierarchy of needs is commendable

Contact them again in 15 years and ask if they changed their mind. Could be interesting to see the results