Let him eat all he can now but if he gets any hint of mouth sores dont eat the pickles. Does he have his peg tube yet? Better to get it now it just makes life easier so remember everyday is different and tomorrow he may stop eating all together. I remember asking the nurse after 10 treatments where we were on the pain sickness scale and she said a 2 (10 being highest) I used Rain Gatoraid via the feeding bag mixedwith water. My husband had trouble with heartburn so I watered it down and he sipped on water. he took food by mouth for 2/12 weeks and then every once in a while for 2 weeks then nothing. He did so well thru the treatment that they talked us into doing more chemo and now he has a severe chemical burn and in the hospital since Monday. Every day is different.