[Just Bill]

Not sure I understand the question. Replace it!! Using drywall is fine. If it is in the shower area and will be tiled, use backer board instead of drywall. Greenboard OK on the seiling.

 

[Ron6519]

where do I start ? some one tore out the plaster in a bathroom two walls and the ceiling?

Try posting some details of the job.
Age of bath?
Age of house?
Are you looking to redo the bathroom or just fix the missing sheetrock?
Ron