I finish the quest to get the skul and return to Grandfather with the information about Melvin. As soon as I try to talk to him, I get an Ohhhh nooo what have you done. Where is my granddaughter. He then disappears and the amulet is removed. As long as I keep the dialogue tree open I can still talk to him and get the quest to find ingredients for the Daggerfall skooma. When I get back with the ingredients and get the amulet again ,the same thing happens. As long as I keep the conversation open,he takes the ingredients and says to return in a couple of days. After waiting 2 days in game I start checking but he never has the skooma. I've tried all the way up to 10 days. So is it normal that he disappears with the same message everytime I try to talk to him? I've tried taking Morgana on the quest and also leaving her behind thinking something happened to her while retrieving the skull. Makes no difference. And am I not supposed to get the skooma or is there something I'm missing? Thanks for any help.

Did Morgana get killed and you then resurrected her?

If she was dead once, all Morrowind dialog consider her as dead, including her grandpa. Obviously he will then not want to give you anything at all.

If this is the case, you should reload the last save before she died.

Thanks for the reply, but no , Morgana wasn't killed as far as I know. I've tried leaving her in Ald-Ruhn during the quest and it hasn't made a difference. The only Npc who has died so far is the witch in Hla Od, and she dies as soon as I finish the conversation without being attacked.

edit;
I went back and loaded the save where I first meet Morgana. After meeting her grandfather, hearing her story, and agreeing to help find Melvin, I walked out of the cellar then returned and got the same message saying What have you done. Where is my granddaughter. Oh noo, then he disappears.