Self centered

He starts to become self centered, he doesn't care about how other feels anymore. He will just simply rant and complain if thing is not the way he wants.
when his wrist watch malfunctions he complain and keep bothering us to take for repair, immediately, if not he be  impatient and keeps ranting you and worse still blames us for not bringing him to solve his problem. He wants it to be done almost immediately regardless of the time of the day, or if we got the time to entertain him.
He has changed completely, and completely lost the ability and sense to care for others.
I know, he is dementia, I should not blame him on his intolerable behaviors, but it is just difficulty to go through it.
After all my mum, the care giver has done for him, it is not the physical tiredness that pisses her off, but the psychology depression of not being appreciated shatters her heart.
And I deeply pity him for losing his care for his close families that if he is aware he wont be so.
Oh please maintain this severity and don't get worse any more. Please