Something I think that is hard to do, but discussing things with them as to what they need doesn't work because they sadly no longer have the ability to understand what they need or why things need to be done. EG when the social worker asked my mum how often she washed, she told her she didn't because she just couldn't understand what the point was in washing - both myself and the social worker struggled not to giggle with the way she said it so earnestly.
I know it is hard but somehow you need to introduce things in a way he can accept them without discussing it.
Something I've seen Canary post many times is she agrees with her husband and then says what needs to be done, so the first word they hear is yes eg yes dear, I know you can manage but we just need XYZ to pop in for now and we'll see how it goes. Perhaps not explain that she will sort out his lunch(if that's what's needed) but then when here, they can put his lunch in front of him and he will probably just accept it.
any reason you can think of for someone coming, eg you have a sore left hand and can't do whatever, and they will pop in whilst you are out, they don't need to do whatever, but if they just breezily walk in the house, saying they are here to do it, and then say whilst I am here do you want some lunch it might be accepted?
In the meantime would a note left saying this is your lunch work?
And can you think of a way you can get a holiday by getting a friend/daughter etc to stay for a few days, or even just one night. I've read on TP of people just going to the hotel down the road just for an evening away from the PWD to do their own thing.
