My father lives with me . His only money comes from social security can I claim him as a dependent

Yes, you can claim him as a dependent.

It is obvious that you provide more than half of his total support, and he has NO requirement to file if Social Security is his only income.

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Even if your father does not live with you, you can claim him if
(a) You must provide more than half of the support, and
(b) your father did not earn more than $3800 in 2012.
Social security benefit is not treated as income but it is support he provided for himself.