can my boyfriend rent his house to my mother if she receives housing benefit?

[zooble]

i live with my boyfriend, who owns his own home, and our child. he is going to change his mortgage to a 'buy to let' one soon, as we need to move to a different area so are going to rent for a while. my mother wants to become his tenant once we're in our new place, but i'm unsure if she can, as she receives housing benefit. would the government pay her rent? we are not married, so legally she is not related to him.

[zooble]

thanks everyone