ah Le Chat, welcome to my world, except mine is a girl! I can tick all of the above plus being told very loudly in a pub/restaurant "don't talk to me as if I am a mong!"
You may also experience new "friends" names being mentioned and, if you care enough by then to ask who they are, you will be greated by "UH! I have told you about them before". Once this has happened a number of times you may feel as though dementia has set in - please then realise that this is the only person with whom dementia is related as you can remember everything other people have told you!
Do not under any circumstances expect to find the same attitude at any time of the day or night. Just when you have resigned yourself to them being a grump bag they will get upset if you do not realise that they are in a good mood, until you spoke to them and it was you who put them in a bad mood!
They may even mention events/parties that are coming up that you won't want them to go to with one of their friends that you have heard about - don't worry there is a very slim chance of this event happening, sit back and wait for them to come up with a reason why they are not going!
Most of all, go in his room when he is asleep, kiss him on the cheek and tell him that you love him. He may not know that you have done this, but you will meet your little boy again, the one not possessed by Kevin!