Heh-you're mixing up two different movies (easy to do after 30 years!).
The ending you're remembering belongs to "The Yellow Slippers". Wawrzek, a sculpting prodigy, helped to create the Altar of St. Mary's Church in Kracow. After the altar was completed, the boy climbed it to make one last adjustment. He slipped on the ladder and accidently lost a slipper (boot) inside the structure. It was a gift from the king for helping to capture a thief, so he was upset. His master informed him not to be distressed, since everyone would see the slipper and remember the boy who left it there. The film cuts to the present, and you see a young boy admiring the altar and seeing an illustration of Wawrzek.
At the end of "Tony", the boy comes out of the bathroom after his "time out", takes a walk with his father (who is now making time for him), and the two make up.