Hi T.,
I think it is sad that he is only seeing his dad once a week, especially if Dad is otherwise a good man who really does love his son. It's just the transition which is hard for your son. My oldest bonus daughter (14) gives her bio mom a really hard time when she comes home from visits at our house because she misses us and wants more time with us. I tell her she needs to be polite and respectful when she goes back home because we will be blamed if she cops an attitude, you know, "Why are you always such a brat when you come home from your dad's?" when really we had nothing to do with it! More often than not, though, she will say she has an attitude all the time because she doesn't like it there, and that her other family will just have to deal with it, so there's attitude upon her return and we get blamed. I hate that!
With my other bonus daughter we had a lot of trouble with that when she would come home (lives with us) after spending time with her bio mom. She just missed her mommy and was upset that she couldn't spend all the time in the world with her, even if she visited almost every day and/or had sleepovers. It was hard on us but we tried to be as supportive and understanding as possible and not to blame her for the feelings she had as a result of the transition between households. It's normal for a kid to have a hard time unless the parents absolutely agree on everything with regards to parenting...and then, they'd still be together most likely!
Maybe this is your son's way to say he misses his dad and wants to spend more time with him. If Dad truly isn't disciplining him, then that's one thing, but if he is just disciplining in a way different from yours that's another animal. Dad is not you, and you are not him, so of course there are two different sets of expectations, rules, consequences, etc. for your son. If yours and your ex's are completely different, you can work with Dad on a set of common rules and consequences for the "big stuff" (i.e. hitting gets T.V. taken away for the day, lying about homework gets you grounded) and it will be easier for everybody. As a mom of three you know kids thrive on consistency; if the households are very different, maybe this is your son's way to push the envelope with BOTH parents to see what he can get away with at each household. It could be his way to vy for your attention, too...if you're working full-time already and also still have your oldest two daughters to take care of (and all their teenage problems, glorious!) your son may be feeling very left out. He may even be misbehaving at Dad's so you will pay attention to him when he comes home.
I'm sorry my advice is so negative, I just know how hard it is for kids when they have two households. As I am married to a great dad who has struggled for years with the every-other-weekend visitation schedule, I tend to lean toward kids spending more time with their fathers (as long as they're good dads). I hate to say it but fathers really do get shafted in court unless there is something very wrong with the mother's situation--that's a lot of power for you to have, and I hope you use it responsibly instead of blaming all your son's challenging behavior on his father. Especially now, as your son is becoming a man, he's going to need his father more and more for guidance and role modeling. Please work with your ex on how to make the transition easier for him instead of limiting him to a couple hours a week with his father!
--M.
P.S. Could it be, also, that he feels alone as the only male in a household full of women? I know it drives me nuts when my daughters are at their mothers' and it's just me, my husband and our two sons...the boys are only three and five, but you can still cut the testosterone with a knife!