My exhusband wants to emancipate our 21 year old son. He is a full time college student and still lives with me when not in school-- summers, brks, etc. I guess he wants to do this to quit paying child support. Can he do this?

No he can't. If his income has changed he may be able to get the court order modified but he can't just get out of paying.

In some states the child being 21 years of age would allow him to. What does the support order say about when support stops?

I thought that if the kid was in college and the court order said they have to pay college then they couldn't get out of it.
I figured she must have a court order and referring to emanicipate as breaking away from the court order because at 21 what would he need emancipated from or for?

The father would have to petition to stop the support (not so much emancipate because he is an adult). Not all support orders have it written to pay through out all of college that's why I asked what the support order said.

There is no emancipating because he is an adult. No matter what state he is in he's an adult.

I think OP means ex wants to get out of his court orders to pay and used the wrong word.
I was trying to answer over looking the word.