Treasure and Tower

Inside the chest are two items. One is a slender gold tube about 8 inches long, finely decorated. If looks like a tube for scroll, but there doesn't seem to be any way to open the cap. The phylactery is magically sealed, and can only be opened with a Knock or Dispel Magic spell. Once that happens, the demilich will be activated and track them down to reclaim it. If the party destroy the phylactery (arcana DC25 to recognize what it is), the lich will be destroyed. If they take it with them unopened, the demilich will reanimate within 24 hours, and try to track them down to recover the phylactery.
The second item is a beaded leather satchel, with a shoulder belt. It is a Bag of Holding, with two items inside it, 3 arrows of dragon slaying, and a pair of levitation boots.
Once he realizes the lantern was responsible for the awakening undead, Mandilissimar will crack and depart, wailing, headed back to his crumbling tower. After the undead have been destoyed, the party can rest safely in the manor. When they go outside, they can easily recognize his hasty retreat up the trail. The trail is visible winding up into the mountains, disappearing around a curve high in the distance. If they take the trail, the tower is visible high overhead.
The characters can reach the tower in about 2 hours, and can move right to the front door. From the outside, it is difficult to understand how the building manages to remain standing. It is four stories tall. The upper floor and the main floor seem to be intact, but the two intervening floors are exposed to the air, with partially collapsed walls and floors and stairs. In order to cure Mandilissimar of his madness, he'll need to have Greater Restoration cast on him. Lesser Restoration or Calm Emotions will give him temporary relief, but the madness can still return or get triggered anew.
Mandilissimar will not recognize anyone as friendly in his exasperated state. When the party arrives at the tower, he is in the first floor. If they call out to him, he will warn them to leave or face his wrath. Then, he will scurry up the tower to the third floor, where he will cast spells from the exposed rubble.