Can my husband's father claim him as a dependent when he provided no financial support?

[Lyn]

My husband is 21 and a full time student (we weren't married during the last tax year). At the beginning of last year, he had two part time jobs and worked more than full time hours. He pays for school with scholarships, personal loans and out of pocket money. Neither parent contributes. At no time last year was his permanent residence with his father. He and his mother lived together (because his parents had gotten divorced and she needed help with rent on an apartment) but both their names were on the lease and they split rent equally ( he paid the owners with a separate check). They lived as equal roommates. He also paid for his own insurance, car, food, clothing and other living expenses. His parents remarried each other suddenly and he moved to a new state with me. He had a full time job lined up before he even moved out and started to work within two weeks of moving out. He lived off his personal savings from his income for that time. We lived with my parents (no rent) until we could find a house, but he continued to pay 100% of all other living expenses himself. His parents contributed nothing to him or my parents during this time. Three months later, we purchased a house . Now, my husband paid for that mortgage and all other living expenses directly from his income. The only things his parents gave him the entire year were holiday gifts and $1500 as a wedding present. My husband has made about $25,000 this year. And does not depend on his parents in any way for financial support, but his parents are still claiming him as a dependent! This makes no sense! Help!