Broken x2

We are building an abnormally tall shed so i can store my dirtbikes, snowmobiles, etc. It is tall because my dad wants to build a second floor so he can store some things we have no room for in the house. We had all the walls up and two rafters, my dad was about to secure the first and second rafter together. Then the ladder tipped and he fell, he landed on his writing hand breaking his arm in two places. He was in the hospital for four weeks. That happened two months ago. They had to cut open his arm then skin graft it, today he is back to work with his bone in place but is not healed.