Do you live with your father? He can only file the I-864A if he lives in the same location as you do. Otherwise he needs to fill out the I-864 as a joint sponsor and qualify with enough income for himself and all dependents.
In previous times, if you submitted the I-864 without a joint sponsor and it was determined that the income is not sufficient, it would be returned to you with a recommendation to add a joint sponsor (or household member). Nowadays however, I would perhaps lean on the side of caution and try to find a joint sponsor as soon as possible and perhaps initially add the joint sponsor, given how intensely Trump has been targeting people who receive (or are likely to receive) federal benefits.