W.O.
we don't have the health problems, but we have coslept on and off for most of her life. Although, now that she is big, she starts the night in her room (I sometimes lay with her til she is asleep) and if she wakes at night and is afraid, she can come to our room and sleep on the floor (I have a pillow and blankets ready for her). She only does it now if she's had a nightmare or is sick. She doesn't ask to come into our bed anymore and is sleeping more and more in her room. I think it helps her to know that she can come to our room if needed.
Also, she has a music player she can turn on if she wakes at night, and has a nightlight. That seems to help too.