I haven't spoken to my mother-in-law in years - I don't like to interrupt her!

It looks as though we might be in for another bad night as the curse of Alzheimer's strikes again.
I used to love Les Dawson's harmless, but amusing, jokes about mother-in-laws which are now so politically incorrect [I'm talking about the gags], such as:

• I can always tell when the mother-in-law is coming to stay. The mice throw themselves on the traps.
• I've just returned from a pleasure trip. I took the mother-in-law to the airport.
• I took the mother-in-law to Madame Tussaud's Chamber of Horrors and one of the attendants said "Keep her moving sir, we're stock-taking!"

Rogue: but Sweep's a hit with old and young

Even my mother-in-law, who lives with us after the death of her husband, used to laugh as the brilliant Dawson reeled off his gags. And tonight she was smiling as she bade us goodnight before pottering off upstairs to bed at about 10.15pm. It usually takes her an hour to settle down ... but not tonight.
As we pass midnight, she can be heard stomping to and from her bathroom [in her shoes because the slippers have been swallowed up again in that great Bermuda-style dementia triangle], sometimes muttering to herself, sometimes singing old tunes.
Earlier in the evening, as we sat watching TV, she urged my wife and I to be quiet and to listen. To what, we thought? She pointed in the air, and said: "Can you hear that. They keep singing Happy Birthday. It sounds very nice but they've been at it for ages. I didn't know it was someone's birthday. How nice."
Alas, nobody was singing, but to an Alzheimer's sufferer, the songs can be very real.
A couple of days ago, she claimed someone was belting out It's a Long Way to Tipperary and last week she heard a choir singing various hymns. "It sounds lovely - it reminds me of the Salvation Army when I was a little girl."

On the march: an East Anglian branch 

Both dogs join us in front of the TV each evening, and my mother-in-law is particularly fond of lovable rogue Sweep. She was frightened of dogs before she came to live with us, but Sweep has changed all that. "I used to walk on the other side of the road if I saw a dog coming towards me," she often says. "But now... oh, I love this little doggy."
Watching TV can be quite demanding for her. We have subtitles on all the programmes to make it easier to follow but alas, reading as well as writing is becoming more difficult. She used to love writing, often read biographies and was a crossword fanatic. An Oxford English dictionary was always close at hand when we called in years ago. Those days have long passed. One down, causing pain or suffering, five letters, beginning with C. Yes, cruel. Bloody cruel.
And following a plot on TV is impossible because her short-term memory is just minutes. She thinks any programme she might be watching, whether it be a soap opera or a crime thriller, has ended as soon as there is an ad break. Whodunit? Who cares if you don't have a memory? Yes, she has lost the plot, and it really pains her during rare moments of lucidity. I might add that the emotion felt by a daughter who is not always recognised by her mum can be equally painful.
Ironically, the BBC were tonight showing a Louis Theroux programme about dementia and much of the show was based in Phoenix, Arizona, a place he describes as the capital of the forgetful and confused.
We decided to record it, rather than watch it with my mother-in-law.
Useful link: http://alzheimers.org.uk/