Stating up front that I am only a well informed patient, it appears to me that the choice to do the surgery first (obviously made by someone of a surgical discipline and training) removed anatomical features in your husband's mouth that are essential for the normal functions that we all take for granted. Like isolating the nasal passages from the rest of the oral environment, articulating his words easily, etc. These days at major ccc's it is more common to have radiation and combined chemo first. This approach preserves as much of the normal anatomical structures as possible, and surgery is left for the end of all this after a determination that the radiation etc. has done the job completely or not. There are still some institutions that will do a surgical neck dissection as a security measure after all is said and done. Surgery first inevitably ends up with long term quality of life issues, and for these reasons when scans (you don't mention how extensive a work up he had before someone brought out the knife) lead a multidisciplinary team of doctors to believe that going with the radiation first (no bone involvement is usually a main criteria) has the best chance of maintaining normal functions. That does not mean that radiation itself does not lead to some long-term issues like life long dry mouth etc.

Depending on what structures where removed in the soft palate and oropharynx, there are appliances that can be made to help restore some of this, but they will not be made until after radiation now, as the tissues will be too sore from the radiation to wear them, and there will be additional tissue contour changes as treatment continues. That means that they would have to be remade again later. So he is likely going to go with these restorative appliances till the end of things if they are necessary.

There is no reason to extract healthy dentition if the patient seems able and willing to be extremely careful about hygiene the rest of their lives. Losing a tooth to periodontal disease after treatment can lead to a non-healing wound and very severe consequences. So old school docs pull them all so it is never an issue, others (like mine) realized that I was dentally aware and would be on top of my hygiene knowing the consequences of failing to do so. 3rd molars are another issue, I kept mine, but they were horizontally impacted and there was never going to be an issue of them erupting into my mouth and causing problems. Given that any radiation treatments will have to wait until the 3rd molar surgery is healed, I might have asked why they didn't take them out while they were doing the rest of the surgery.... it would have moved you into the rest of the treatment process faster.