Advice needed

Hello!! My baby boy Sam got in an accident which has resulted in multiple cuts and scrapes and three broken toes on how left rear leg, our only option is to amputate, due to the positioning of his injuries.

He is having surgery tomorrow morning, and I was just wondering if you guys have any advice on how I can make this transition easier for him, and if I can help him in any way adapt and adjust to having three legs. Any advice would be really appreciated!!