Hi
Sounds like he might have a little infection which has made him miserable. This would also make him feel like he is not progressing. I found with Alex that initially, his recovery could be measured day by day and he was very encouraged and then he sort of plateaued at 8-12 weeks which made him feel he was going backwards. A lot of our dialogue went " you are much better than this time last week/month/year, when you couldn't .... " just to remind him of how far he had come as he sometimes couldn't see it for himself - especially when he was having a bad day. Being able to track back through emails and journals to remind him of his trials and successes has been really helpful to show him that even though he feels he is going backwards, he is actually going forwards - albeit more slowly than he had hoped.
I also think that early on, the survivor is so busy concentrating on just getting through the treatment, they don't even notice the other aches and pains which fade into the background in comparison. When they start to get better, they start to notice all the other stuff which makes it feel like they are getting worse.
Regarding the symptoms: The sensitivity in the fingers may be chemotherapy after effects (carboplatin). A friend of mine described a sensitivity to heat and cold to the point where touching something in the fridge could sometimes cause a sort of electric shock in his fingers. There is also something called Lhermittes sign caused by radiation, and which I only found out about last week through these boards. If you think it also sounds a bit like what Simon is describing, just search for Lhermittes as there is a link there that describes it rather well.
I am interpreting your description of "pain in his eustacian tube" as earache? If so, a GP could easily check his ears as he might have a plug of earwax in there giving him a hard time which could be flushed out by the GP or his nurse. Radiation also causes the earwax to dry out a bit and it can get "stuck" in the ear canal and cause pain. Also infection could be the cause and it may just be a case of time or antibiotics.
Dry mouth which causes broken sleep is also commonly described on the boards and people have suggested humidifiers to help. We have no experience of this so will let someone else talk about this.
The very good news is that he has a sister who loves him, supports him and is doing her damndest to understand his issues. Oh, and he doesn't have a temperature and the aches are receding which is also very good news.
Karen
Love of Life to Alex T4N2M0 SCC Tonsil, BOT, R lymph nodes
Dx March 2010 51yrs. Unresectable. HPV+ve
Tx Chemo x 3+1 cycles(cisplatin,docetaxel,5FU)- complete May 31
Chemoradiation (IMRTx35 + weekly cisplatin)
Finish Aug 27
Return to work 2 years on
3 years out Aug 27 2013 NED

Still underweight