Help with potty behaivor

A little background first.  I have been raising my grand daughter since she was two years old.  Her mother was on drugs and CPS was involved.  As stressful as it was for me as a single person, it has been a releif and a joy.  However, this child has experience a lot of grief for so young as a child and showing it through her continence.  She came to me with her half brother two years ago and we adjusted quite well.   They had a routine and a predictable environment for the first time in their lives.  However, parents of both children were practically non existent.  Brandon would tease her about not having a father since his father did contact him by phone.  I would assure her that she did indeed have a father, but he did not call as much.  That was short lived when we found out that he was killed.  I think we did alright with the transition into “daddy is in heaven” conversations, and all seemed well.   Then a year ago, her brother went to go live with his father despite my effort to keep them together.  She would talk about him and how she is waiting for him, but doesn’t seem stressed about it.  I now have custody of her, so her situation is secure.  

I never pressured her to go potty and used the reward system until we were potty trained during the day.  Even though she just turned 4 years old, she remains in a pull-up at night with out pressure; just encouragement to have a dry one in the morning.  However lately after a visit from her mother, she urinates in her mat at school during naptime even though she is awake.  She does it for one day only and then and not again until the first day after the next visit with mommy.

The whole situation is quite sad and I want to do what is best for her.  She is bright, happy, and loving and seems adjusted except for the day after her mother comes over.  I don’t know what to do.  Should I ignore it and let her mother come and go until she grows out of it?  Her reaction is so predictable that I believe it is a behavior issue and not a physical one.  I want to tell her mother to either come frequently so that this child knows that there is a tomorrow with mommy, or don’t come at all. I just don’t know what to do.

[Liza55]

First, know how wonderful you are to sacrifice to provide a positive life for these young children. How different their life could've been w/out someone like you to step up. Someday they'll understand and appreciate what you are to them!
Clearly the stress and all it brings back seeing the mom again is associated w/ this periodic loss of potty training progress. I think you're already doing everything right by not forcing anything or punishing her. Perhaps you can contact a psychologist to help get to the bottom of what she goes thru after seeing her mother. Otherwise I imagine the more time she has w/ you and a stable, predictable and safe environment will bring about less of these episodes. I wonder if the visits are happy or akward or somehow scary for her...does she think she'll have to leave you if her and her mom get along? Is that a possiblity?  Again...probably a child psychologist is needed....good luck