I dont know but maybe not because shes seeing Payson happy about her new life away from gymnastics but i was so happy when Sasha told Mrs. Keeler that Payson can do gymnastics again.
But i hope she will tell Payson about the surgery *fingers cross*
I think she won't, at least for some time cuz that's an opportunity for a plot twist and a whole new mess since Lauren got so lazy ;P Plus, I think that Kim is too afraid that will be another disappointment and she couldn't stand seeing Payson like that again. She probably thinks that now when she finally adjusted it would be too much of a risk.
Yes she is a good mother and wants the best for her daughter and wants her to be able to make the decision and be able to know that there is another option in her life