acknowledge that there is any problem and my Dad will not force the issue or even take her back for more testing. He has just given up. I feel that we have already wasted too much time and would like to get her on medication before it's too late (for it to make a difference).
When my dad got critically ill and was hospitalized, the attendings put him on 5 mg Aricept. When I did go to the neurologist later, he said to me, "This is clearly Alzheimer's and he is not on a therapeutic dose of Aricept. We raised it from 5 mg to 10 mg.)
My dad improved quite dramatically. This allowed us to go visit his grandkids, for them to play and remember him and for him to remember them. After a year, we discontinued the Aricept -- it didn't seem to make any more difference. (This is normal - effects most prevalent in first year)
Every case is different, but I think it's obvious your dad's physician isn't treating or acknowledging his dementia, and when two family adult children recognize something is amiss, it's time to find a new doc. ASAP.
That's regarding your mom.
It also sounds like you'll need several new strategies to help your dad cope and to deal with the situation, if he can't. Maybe some others have some tips in this regard.
For my mom, once she was evaluated by a memory specialist, she saw the geriatrician. He did blood tests and a CAT scan to rule out other dementias. Then she was referred to a geriatric psychiatrist to make the final determination. Start to end this took about 3 months. Once they determined she had Alz, she was prescribed Aricept (along with other things) and we did see improvement.