I lost my life long (2nd grade) best friend this past April, very sudden. Her Mom is still alive at 93, but time is limited and she fades in and out. I've tried speaking with her but it's not a satisfactory conversation for all involved. Not having my friend to talk to, especially since losing my other best friend, my sister, back in 2014, it's quite an adjustment. It kind of gets easier over time, sort of. There are moments and I'm sure you will experience them. Hopefully contact with your friend's daughter will help ease those moments, as well as comfort her also.
Wishing you peaceful and poignant moments.