Need wisdom

[stepmomat]

Brief background:

SO has primary custody of 2 boys (8,7) since 2003.  Schedule is 50/50 during summer but during school year mom gets Tues. after school until 6:00; every Thursday after school overnite and every other weekend.  She is not cooperating with SO with anything regarding boys and is extremely PO'd that she pays child support.  Children are doing well in school and we have them in counseling for some issues they have to deal with regarding mom.

Problem lately is this.  Younger child has been saying why can't we do one week on and one week off or asks why they can't stay overnite on Tuesdays.  This is something new and when we asked him why he said cuz that's what mom said to him.  However, during the summer they both complained of spending so much time at mom's cuz she never does anything with them and they can't go outside to play, they can only play inside or play video games (all day).  

How would you answer him?  She doesn't have a change of circumstance to get back into court (she's tried 3 times in the last 4 years) so it seems she's going to start messing with the kids minds.

How you would handle this situation????  Remember, he's only 7 (the 8 year old is keeping quiet)

Thanks so much for your help!