Hi Jan ..
this IS a confusing time for everybody isn't it? Nobody quite knows where to put themselves .. it's a bit like treading on egg-shells because you don't know what might trigger a behaviour.
You know, sometimes there is no trigger ... they just "turn" ... it's a real Dr. Jekyll & Mr. Hyde kind of thing sometimes ... and all you can do is reassure them, comfort them and try and divert them.
There is a gentleman I know who, immediately after lunch starts his sundowning. He's obsessive .. each day the obsession is different .. one day he needs his car NOW (hasn't driven in 5 years) and he's so CONVINCING that the car HAS to be in the car park outside, and if he could just move it all would be well. Well, he's not allowed out of his area, he needs to be contained .. ... another day he needs to speak to the bank because he's being ripped off .. and there is NO placating him when THAT obsession starts ... another time he MUST know where the children are and no matter what answer you give him, it's not the answer he wants to hear ...
and this goes on for HOURS and HOURS until he can be put to bed .. it's
EXHAUSTING !!!!!!!!!!!!!!!!!!
Then out of the blue, one day, he'll approach and tell us he knows he has a memory problem and he's sorry if he can be difficult sometimes ......
awwwwwwwwwwwwwwwwww
he's been doing this for a year now, but he's an unusual man LOL

LOL
I have found they are usually pretty good in the morning too, probably after some proper rest .. is there any way you can get him to have a nap straight after lunch? It's not always easy .. but you can give it a try. Does he have a shower in the morning or at night? Perhaps a shower might help settle him (won't hurt to have 2 showers a day if need be) ... what's his FAVOURITE chatty subjects? I have found talking about animals can be a good diversion sometimes .. even putting some kind of animal movie on the TV can be a good distraction at times ...
It's NOW you have to be inventive and tell little white lies to keep him as calm as possible so that the family unit can remain as calm as possible. Don't try and argue with him, its frustrating on both sides, if he thinks the lawn looks shoddy, tell him you'll speak to the 'help' and they will fix it ... take him to the lawn later and show him what a good job they did fixing it (little white lies: eg: See this bit they missed before? Isn't it great now?) acknowledge that in his mind what he saw was right (makes him feel better) and show him it's good now (creates the peace).
And .. write down the funny side of things .... it will help YOU .. I had one gentleman telling another person about me, and he kept calling me a "he" .. well, I just quietly pulled my shirt out in front of me (to check I still had breasts LOL) and said quietly to nobody in particular "I'm sure I'm still a she" and then he turned around and said "and not a bad sort either" .. HAHAHAHAHA ... yet then proceeded to keep calling me a HE !!!! LOL LOL LOL
Big hugs mamaduck ...