Who is Mr Collier from The Lottery Rose and what is their importance?

Mr. Collier is Molly's father. He is described as an intelligent, smart, and kind older man, who after the deaths of Paul and Mr Harper, moves in with his daughter. He wants to help raise Robin and as well as help his daughter get over the loss of her husband. Mr. Collier was once a professor at a prestigious university, where he taught young people how to become teachers.