Wife wants parents to come to the US for a visit. Mother needs to sponsor. What are the risks?

My Chinese wife (grren card) wants her parents to visit. We are expecting our first child and wants them there during the birth. My mother would need to sponser as we lack the funds. -No jobs. I doubt her parents couldn't self sponsor so it up to my mother. My Mother, however, fears their might be some kind of risk. Perhaps a finacial burden if something happens. IS their a risk? we'd have travelers Medical Insurance on them both. They don't speak English and probably wont go out much except with my wife or my wife's friends. IS their a risk? and if so, what are the alternatives if my mother declines to sponsor? We'd stay in Oregon the whole time.Thank you.