Three months is not long for a rehomed tiel and you do not know what hands meant in the last house. If he was ever grabbed or toweled without anything good attached to it, he has already learned what a hand arriving means.
So rebuild it cheaply. Sit near the cage and read aloud or whistle without trying to touch him. Millet through the bars, then from your fingers, then from a flat palm. Approach at his eye level or below, never down from above, which is how every predator he has an instinct about arrives.