2008 tax question, yes, thinking ahead ?

[Sheila]

Only a few years ago my divorce/child support agreement was modified, when my two older boys were 14 & 16. In the original agreement I had custody of them and claimed them both on my taxes, all those years. In the modification I kept claim to the older son, now 19 and in college and my ex got claim to the now 17 year old. The 17 year old finally got a job in a restaurant, so will have a W2 for 2008. He also turns 18 in December 2007. We/he will not want him to be on his father's taxes anymore. For one, his Dad would have to have his W2 to do so and secondly, I also know from all the leg work I did for my older son's college finances my ex is getting his 1098T, when that time comes, over my dead body. So, it would be easier for this son to break away from his Dad's filing for 2008. How do we tell my ex this? And what happens if he, as he has a domineering wife, files with this son on his taxes anyway, without his W2 and then my son files himself, claiming himself for 2008?