what to tell the daughter?
When she asks why doesn't Khas love you best any more, there are two truths you can tell her.
'I honestly don't know, and what I do know is that loving longest matters more to me than loving best. Khas's love for me is going to continue, and that matters more to me than anything else'
The bit about his love continuing is what she most wants to hear: I think she will get what you're saying. and she will know it is the complete truth too, cos remember she knows you too.