I seen my deceased grandmother at the bottom of my bed...?

Your Grandmother has come to comfort you .Take peace in that and tell your mum to tell your dad to come home if she wants him too.Was a good attempt to manipulate you though.If Grandma tries to tell you something the next times she appears try hard to listen she is not there to hurt you. Ghost are real and are there to help ,guide and protect us .You are soooooooo lucky to have seen her.