I think I'd thank your friends for the "gift" when you see them, but not offer any additional comments, or if pressed indicate "the book certainly was interesting." I doubt that they paid the indicated $28 for the book - probably there was a reduced rate for ordering extras. Yes, a thank you note if you would have sent one for the Christmas gift, and no, I don't think you should change your Christmas shopping habits for such a tacky gift (unless you run across something that does reflect your view that you want to share with them!
Dmom's doc called and she does have a UTI and her sodium is also low, so both are valid reasons for confusion. The in town pharmacy she uses is notoriously busy so I am planning to pick up the script tomorrow and see her to explain the meds and that she can eat more sodium for the time being. Dbro could in theory pick up the meds but I'd rather integrate it into her meds container so meds will get taken regularly. Doc said blood sugar on the high side, but she wanted to straighten out the UTI first since that can also cause a rise in blood sugar.
I am going to read for awhile....