1974 yes, he's attention seeking; always has been. Sounds very much like your situation-mollycoddled, pandered to, always the centre of attention. However although he can be manipulative, I don't believe him to be a nasty person. He can be quite kind, albeit in a rather self-absorbed way.
What he DOES do is create illnesses. Or I think he does, at least. He's worked out that he gets lots of attention and sympathy if he has something wrong with him. To be fair, he does have things wrong with him, which deserve sympathy. He has no bladder function, for example, and uses a bag.
So, if our other cousin, who is older, gets something wrong, dcousin has to have it too, only worse. Trouble is, he forgets about it, then invents something else, like suspected bowel cancer. He gets the tests, which prove negative, then he moves on to something else. He's in the Doctor's practically every day, and is constantly having tests, quite often privately. His mother had pernicious anaemia, which is deadly if untreated, so, a while back, he had tests for this too, which according to him proved positive. However he hasn't mentioned it since, strangely.
His latest thing is artery problems. His dad died at 55 of a heart attack, so my cousin has had numerous tests, some quite invasive, to prove that, actually there's nothing wrong with his arteries. All these illnesses, whether real or imaginary, create opportunities for him to seek-and get-attention.
However despite his concerns for his health, he has no interest in self-help strategies such as exercise or healthy eating. He's only interested in pills and tests; ie attention-seeking opportunities. Nothing dramatic, but I DO sometimes suspect that the "stealing" could actually be another cry for attention. I feel awful thinking that.