I am going through something similar with a dcg that is 3.5 yrs. Mom and Dad work shifts (they are nurse and emt) and are constantly giving me excuses when it comes to why she does fine here but won't go at all at home. They are very indulgent parents and say that it's hard when you work shifts or dcg doesn't want to sit on potty and when they ASK her to sit, she changes the subject!!! Are you kidding me?
Mom like to use every emergency case that has ever been told to her and says she doesn't want to make her go on the potty because it will traumatize her and she will hold it and get a serious infection.
I'm sorry, but before I started daycare, both my hubby and I worked shifts and we did fine with our 2 boys. I too am getting grossed out by changing a child this age. I am definitely thinking of putting something about training in my handbook. I feel like I am the only one willing to make an effort in this relationship...it's very frustrating