Well if heated greatly in the process it would denature the protien more. That said now a days with Whey being so wide spread and in demand/competative id say MOST are OK sure some better than other, the various methods used. Iso filtrations, Micro filtration, concentrates, isolates, Hydrolyzed, its endless.
Id say go with a Quality brand, AHH and Id say Look right HERE at Meteabolic Drive. Its a Whey Casien Blend. Check Out the product thread. the Micellar Casien being VERY lightly processed and not damaged. Etc and they stuff is Fan damn tastic for taste.
I will add I began having my Mom use it when she was diagnosed with Cancer. Gave her three months to live. Well shes passed now but not before we had 4 good years. Ill say that a good diet including the Metabolic Drive, as well as regular exercise and Just a Lot of FUN and Love were directly responsible for the length of time we had.
Be proactive for sure in her battle. dont sit aside. I wish you both the best,