How is your dad doing now? I am in the same position as him. Savoury foods taste horrid and I have a PEG tube. The doc said to me I may have the tube forever as my mouth can not open fully due to the radiotherapy, I find it difficult to swallow, have no saliva and taste buds have changed. I do eat porridge - ready break or the microwave oats. I eat them with honey or this maple syrup with 25% less sugar mixed with carob. I have recently been adding blueberries to challenge my throat - this has been good. Soups - add honey to carrot, sweet potato and lentil soup, miss out pepper, onions, cooked tomato or anything with a kick as it can be nasty on the mouth. I find ice cream hurts me but it may be ok for him. I eat a lot of yogurts and panna cotta is amazing! Multi - grain shapes cereal is lovely. Also Lindt lindor has been a great find because it is melted chocolate on the inside and soooo soft, thorntons do some soft centred chocolates too. They come in boxes of the truffles. Yummy. I also tried a little bit of very soft roast chicken breast with gravy and was amazed to like it!! It was a challenge but go slowly and drink water. Fish in sauce boil in bag with petite pois peas and quinoa (very soft and protein rich) has been a savoury meal I enjoy because of sweetness from peas. If all the dairy is too much then try soya milk, they come in different flavours. Also, the Green and Black's chocolate cookbook has a yummy chocolate pot recipe that is heaven. Smoothies are good. There is one I make with banana, protein shake, spinich, milk, sometimes blueberries, sometimes a healthy oil like Flax or Hemp, blitz upped - tastes very good, honestly. On diagnosis we went a bit mad and bought an extremely expensive juicer so I could be try maintain good nourishment that way bt many of these juices nip my mouth so I am still doing trial and error with it (determined to find some super green juice I can manage). There are some books on the market as well if you search amazon for 'difficulties swallowing' (if you need to know these titles specifically just let me know)http://www.cancerresearchuk.org/cancer-help/coping-with-cancer/coping-physically/diet/managing/soft/soft-diet-meals
is also helpful.
Yes the sugar is not great for us but what are we meant to do! Not eat hardly anything? Not have any pleasure? Also, please I hope he has having his feed now. It is important to get full nourishment after all the treatment.
Good luck. If you have any tips for me that I haven't written here, please share, it is hard work and very isolating, especially as I loved food so much. Remember to drink tonnes of water, herbal teas and my fresh homemade lattes from a machine with frothed milk (using a frother) is another little but treasured pleasure.