Dear dhdebbie,
I'm so sorry that you and your husband are dealing with PC and that the treatments have been so hard for him. From what I've read and experienced with my mom, the PC would not get worse BECAUSE of the chemo, but DESPITE the chemo, meaning that the chemo has been ineffective. I have heard of cases where people were candidates for surgery, and then at the last minute not be candidates, and vice versa. I don't think the PC gets worse on chemo, but the patient most definitely may FEEL worse, and have many side effects because of the chemo.
In any case, most importantly, DON'T LOSE HOPE!!! Going through chemo just simply sucks! Maybe you can look into better pain/anti-nausea medicines with the doctors/nurses. Once we found the pain nurse for my mom, it made such a difference. Try to check on this site regarding menus for anti nausea during chemo treatments; I know I've seen such posts. When do you have blood tests/scans to ascertain whether the folfirinox has been effective or not?
Hang in there! Thinking of you.
Punky