hi UKGuy, love this insight! thank you!
I never felt that Burke had autism. obviously, we don't know everything about Burke or autism even, but from what we do know I've just never connected those things. he seems to be very aware of reality, just not interested in it, which is more in line with asperger's.
it is my feeling that Patsy may have had trouble bonding with Burke as an infant. this initial bonding period between mother and child is very important to a child's development. usually it is because of the mother — Patsy may have had post-partum depression, or simply be frustrated with her sudden responsibility to someone who isn't her. Patsy is very self-absorbed — she wants to do what she wants to do. a baby throws a wrench in that. however, it can also be because of the child... if Burke does have some mental issues, that could have been with him even in early childhood. he might have ended up colicky or cry a lot, not be cuddly or reach for his mother, which can be upsetting to a mom. children who become sociopathic or psychopathic are always sited as lacking a physical + emotional bonding phase with their mother in the first 2 years of life. I don't think Patsy is very physical and I don't think she likes getting dirty, and kids are... well, dirty, at times. a nanny was introduced fairly quickly, I imagine, to keep Patsy sane. Burke likely didn't spend a lot of time with his mother which forged distance between them.
additionally, Burke is a boy. he is quiet and takes more after his father in interests and personality. he doesn't resemble Patsy really at all. narcissistic people have difficulty relating and connecting with people who aren't like them, and I believe thats the case with Patsy with Burke vs. Patsy with JonBenét. Patsy passed off Burke to John in her mind, even before JonBenét was born. and then, of course, JonBenét was a mini Patsy. Burke was just Patsy's kid. I think in terms of emotional attachment and parenting, Patsy was the same with both kids: I think she viewed the responsibility as tiring and beneath her at times. JonBenét was just more "fun" for Patsy and had the benefit of possessing a personality and interests that Patsy had, which satiated Patsy's need to be emulated and feel superior as a narcissistic individual. I'm sure Patsy rewarded JonBenét with her affection a lot more than Burke, because JonBenét did things she liked and that represented herself and Burke didn't really. Burke was an after-thought for Patsy because she didn't feel anything in common with him, and instead of conforming to what her child needed, she stuck with what she wanted. lots of parents do this, sadly.
if you read Patsy's memoirs about her daughter, she refers to her very selfishly — "she wanted to wear evening gowns, just like mommy", + using words of possession such as "my child" or "my daughter" instead of saying her name. I also think it's telling that JonBenét Patricia was named after her parents John Bennett and Patricia, whereas Burke is just Burke... with no obvious connection aside from the shared surname.
Patsy's disinterest in Burke during his initial years probably contributed to his quiet and reserved nature. he learned to be by himself and therefore didn't express himself. JonBenét comes along, and he sees something different. in someone with personality traits like Burke jealousy might end up reading as disapproval. he may have developed an ego due to low self-esteem influenced by a lack of attention and encouragement from his parents. by the time JonBenét was born, Patsy and John had become more accepting and used to their role as parents, and were more engaged with their daughter in her formative years. Burke and JonBenét were raised with different levels of engagement from their parents and I don't think many people dispute that, despite not being proven.