Hi Shane. My mom had the same problem with swallowing during and after chemo. The pain was intense. She tried numerous things prescribed by her Onc, nothing helped. Desperate, I turned to Doctor Google. Found an article from the Mayo Clinic that suggested peppermint may help as it relaxes the muscles in the esophagus. I went to the drug store, spoke to the pharmacist who said peppermint hard candy wouldn’t hurt and could help. Bought a bag and raced to my Moms house. She sucked on the candy before eating and it actually did help! Maybe placebo, maybe mind over matter? Not sure but it gave her a little relief that she desperately needed. Peppermint tea also seemed to help a little. I nixed my moms suggestion that peppermint schnapps might help as well.
Hope your dad is doing better. It’s so hard to watch them struggle. Hang in there.