My Husband And I Had A Baby Boy That Was

My husband and I had a baby boy that was born 3 weeks and 1 day early and weighed 5 lbs 9 oz. We live with his mother so she can help us take care of our son. For the past couple of nights, she has been taking our son into her bedroom for him to sleep with her. She has 2 dogs that are miniature pinschers that can be very mean at times. I can't sleep at all within those past nights because of our son not being in our bedroom to where it has me stressed out and crying. This is my only child, but my husband's second. I don't want anything bad happening to him where he dies from SIDS or anything like that, especially with him being so tiny. As I read online, it said for babies NOT to sleep with anyone and to sleep in their own beds due to them being at risk for SIDS (who knows if it's actually true) I'm too afraid that our son will roll off the bed and hurt himself very badly or one of her dogs attacks him to where we have to rush him to the hospital for either one. I apologize if I sound like I'm a crazy overreacting mother, but it has got me so worried especially with me being a first time mommy. If I dare say anything to my mother in law about it, she will kick us out in the freezing cold and make sure that we have no place to live. What should I do?