Titus Gragg served three times during the War of 1812 with Captain Samuel Whitesides: once with the US Rangers and twice with the Illinois militia.
His service records are in roll box 83, roll records 963, 964 and 965. From my records, he did not receive an Old War pension during the War of 1812. If he or his wife lived after 1871 when there maybe a service pension issued.
You need to write to the National Archives for his service records and to see if he has a service pension.