Producers brought in five - year - old Billy ( Jonathan Halyalkar ) whose grandmother left Billy in Tony 's care .
Five - year - old Billy ( Jonathan Halyalkar ) is a kid from the Micellis ' old Brooklyn neighborhood .
Producers brought in five - year - old Billy ( Jonathan Halyalkar ) , a kid from the Micellis ' old Brooklyn neighborhood , whose grandmother left Billy in Tony 's care .