Ok this is going to sound a bit stupid!
I got 2 cats as kittens a year ago. One (DCat1) was very friendly and chilled, very content with life, ok with being in the living room overnight as a kitten, happy to be picked up, would come to us for a fuss etc. His brother (DCat2) was originally quite happy to be picked up and would sit on me, but over time has become far more aloof, doesn't sit on us, doesn't like to be picked up etc. However, despite seemingly not wanting me to stroke him, he continually meows at me!!
We went on holiday in May 2024 and they stayed in a cattery, and after that DCat2 objected greatly to being in the living room overnight. Would wake up early in the morning and jump up at the door handle to be let out. This drove me up the wall, so I started letting them have free roam of the house overnight. It took a while for them to settle into this, as they were only about 6 months old at this point, but they were ok - in and out of my bedroom but would also go outside through the cat flap and all was well.
DCat2 however would still meow at me early in the morning for "breakfast", usually at about 5am. I would go and feed them both and they would usually go outside and I'd go back to bed for a couple of hours. This was not ideal, but not awful and definitely better than door handle rattling, so I just kind of went with it.
Sadly, DCat1 died at the end of November. Since then, DCat2 has been more "needy", as in meowing at me more, but nothing I seem to offer seems to be what he wants. He does it in the middle of the night, and if I don't respond, he will go and rattle my son's door handle, which he knows I will respond to as I don't want him to wake up my son! I will often go downstairs with him at this point (this can be anywhere between about 2am and 5am) and I'll feed him to keep him quiet, even though I don't think that's what he wants (he doesn't eat a lot, unlike his brother he is not at all motivated by food). I know I'm probably reinforcing the meowing, but I'm not sure how to manage this. I feel terribly sorry for him as his brother only died a month ago, so I would feel really mean shutting him out of my room (I suspect he would go mad anyway and wake us all up with meowing/door handle rattling) but I've had 6 months + of disturbed sleep every night, and I can't deal with it much longer.
What does he actually want?! It predated his brother's death, so whilst I get that he is probably missing his little buddy, I don't think it's (just) that. I need a cat whisperer!