live in bf kids have deceased mom, what to do??

From my experience on having a son die and 7 dds who have to live with that fact. I would say, always be open to what they want to talk about and when. For us when people talk about our little boy it is like he is still around and a member of our family. From what you said it sounds like you are doing a wonderful job. It can be awkward knowing what to say about the loss of someone so dear. I want to give you a big these children are blessed to have someone who is willing to try and be supportive of their grief and allow them to express what they need to express in their own time table.