In the book "the tales of Despereaux" why did Despereaux forgive his father?

Lester Tilling is Despereaux Tilling's father. He sent his own son to the punishment of being exiled to the dungeon, where the rats would no doubt eat him. Later, after Despereaux escapes the dungeon on Gregory's tray, Despereaux pays a visit to the Mouse Council, which pronounced his sentence. Lester is forgiven for the perfidy he committed against his son.