I’d ask my Mom if I could see her will and other documents that reference her care. I’d also approach her husband to get to know him better and talk with him about what role he would like to take in her care and what role you can play. If this were my Mom, I’d be suspicious as you sound. (It’s a good idea to discuss this with a lawyer even if you think that he can be trusted.) I’d also go speak with her doctor if you’re seeing she’s becoming physically dependent and needing care.