I am sorry to read that your son is still sick. I do hope he's feeling better today.
I'm glad W came back over and enjoyed her gifts and cake. It sounds like she's finally settling down and bit and wants to spend time w/the children and doesn't have an issue w/spending time w/you as well. Sounds like she's been doing some serious thinking if she's willing to move closer and not disrupt the children's lives by uprooting them every couple of weeks. Her plan can work, but you'll need to make sure that you don't have anything lying around that you don't want her to see when she's over there during her visitation time, if you are out for a period of time.
You are doing a great job of being patient, compassionate and yes, willing to work around her crazy making. Keep up the good work!
P.S. Time to start a new thread.
Sit quietly, the answers will reveal themselves when you least expect them to. The past is gone, the present is a gift and you need to focus on today, allow the future to reveal itself when it is ready.