It is also great that you family is supporting his desire to quit smoking by joining him in doing that. He will have a much better chance of success if they all do it together.
When I came home after my heart attack my family all went on the Pritken Heart Diet so I wouldn't see them eating steak while I ate fish and chicken. It made it so much easier for me to avoid temptation that way, and that will help your Dad too.
Don