Something So Right (1982)

Joey lives with his mother. His father isn't around, he doesn't like school, he is bored, and he takes orders from nobody. In other words, he is a real little scamp. At her wits' end with him, his mother decides to look for a "big brother" (a sort of surrogate father) for him. At first, this clumsy Arnie doesn't know how to handle Joey, but after a while everything changes--and not only for Joey.