My 90 Yr Old Grandma Just Had Her Gall Bladder

My 90 yr old grandma just had her gall bladder removed she started with nausea Fri not wanting to drink or eat we got some fluids in but not enough. Took her to er today and they removed gall bladder and said it was completely dead and gangrene. How long does it take for a gall bladder to completely die and turn like that she never complained of pain until Fri then not really pain just stomach ache