Is one obligated to repeat the Fajr prayer if the worshiper experienced extreme drowsiness during the Tashahhud and does not remember whether he said the Taslim or not?

It is recommended for the worshiper to interrupt the prayer if drowsiness and sleep overcome him, until it leaves him. For if he prays while drowsy, he may curse himself instead of seeking forgiveness. The prayer of one who is aware of what he says and does in it is valid, and a doubt that arises after the completion of the prayer does not affect its validity. Repeating the tashahhud does not invalidate the prayer. As for doubt concerning the taslim (salutation) at the end of the prayer, if one did not perform the taslim at all, or performed it after something occurred that makes rectification impossible, then the prayer must be repeated.