Im sorry to hear your husband is having a problem with eating from the mouth issues from rads!!! The first thing I would always check with is his doc, if he hasnt already mentioned this to his doc. Since your husband is only 3 weeks post rads, he is just beginning his recovery. Often patients and their caregivers can feel a bit abandoned by their medical team after losing the daily contact they had during rads. Even though your husband completed his treatments, he still is under the physicians care so dont hesitate to call his doc and take your husband in to get checked. His mouth must hurt like heck!!! I suggest not trying to wait it out until his next appointment, call the doc and get him checked out. Often the rad nurses have the best suggestions as they see patients every day instead of once a week like the doc does so ask the nurse too. If he doesnt have and use magic mouthwash ask for a prescription to try it to hopefully numb his sore mouth to enable him to eat easier. Also, ask if the treatment facility has a speech therapist who can help your husband to better maneuver food or talking in a way that will not cause any other continued problems. I definitely would not wait to make the appointment to get him checked out! Right around 4-6 weeks post rads, patients notice their thick gunky mucous suddenly changes seemingly overnight into the dry mouth phase. The dry mouth for most of us will hang around for a long time. When it starts to kick in, your husbands mouth issues probably will get even worse. Ask the doc about pilocarpine (a prescription medication that may help increase his saliva production) and also ask the doc about using things containing xylitol to help with low saliva production.
Im guessing he has noticeable swelling from rads like most of us have had. In time as the inflammation goes down his mouth shouldnt be so sore from use. Im sorry to say most patients in their recovery phase can get frustrated by their rate of progress as its not what they feel what they should have. Unfortunately patients who have gone thru so much already also go thru a long recovery. After rads, patients will heal at a much slower pace, with it taking longer than any of us expected or would like it to be. It takes the body 2 years to make a complete recovery, some patients have reported they've noticed improvements even at 2 1/2 years after finishing rads. Its usually improvements in the patients sense of taste and saliva production where they notice a few late recovery improvements.
Wishing best wishes to you both. Hang in there!!! Better days are ahead