After the shock of Andrew's death had passed, Allan went often to his step-grandfather's grave and mourned for what had been and what could have been had he known Andrew for longer.
From the Leaf-Pile in the Sky, Andrew could feel his transparent heart melt. He had not known Allan or his father Chris for very long, but they seemed like good people. He found Pam and convinced her to join him in visiting their daughter and new family.
Pam looked around at the house and was happy to see the couch and TV hadn't changed any. But this wallpaper! Surely her daughter had more taste than this. And if Pam wasn't mistaken, that blue fellow sleeping in Kath's old bedroom was just a little too strange.
Nobody had told Pam that her daughter had taken in a vampire kid. Her reaction upon finding out was... less than encouraging.
Personally, Andrew didn't care if Allan was a vampire, a werewolf, or a cow mascot. In his past life and then in his past ghostly visits he'd grown to love Chris and Allan. They were good people and they'd take good care of his daughter. With this thought in mind, Andrew let Pam go elsewhere (death do us part, remember?) and continued to watch over his family.