Here we have an old plaster type ceiling which has collapsed just due to age. Sometimes the quickest/best way to patch ceilings like this is not to patch them at all, but to simply put a new sheetrock ceiling right over it.

Because there is no water damage, there is nothing to worry about with mold. And because it's an old surface it probably has lead paint on it, so it's often better not to disturb it at all.

In an old house like this, covering the ceiling of a bedroom usually takes about 6hrs of labor and $50 in materials.