My son's father is scheduled to have visitation every other weekend. He has been very sporadic with his visits and in the last 6.5 months hasn't called or shown up. Out of the blue I received a phone call from him saying he was going to take him next weekend (his scheduled weekend). After the phone call I realized that we have a cub scout activity Friday evening and basketball Saturday afternoon. He has said in the past that our son should cancel all activities previously planned on his weekends, can I do anything so that my son can still attend his activities?