I can write off my son as a loss?

I invested at least $80,000 in his university education (tuition fees and living expenses in another city) in his 4-year education. Now, he has told me that he didnt like what he has studied at the university, and he does not like to live in the same city with me. He now lives in another city, and my frequent phone calls to him have been seldom answered. When he answered, he often asked for money. In many ways, it appears I have lost everything (emotionally at least) that I have invested on him.