I just googled is jealously and ASD linked. My little is 5yrs old. He’s very jealous of his little (2, almost 3 yr old) cousin Kayden that lives with us. Kayden is very independent. He will do his own thing all day long. My little one wants his little cousin undivided attention and to look at him and what he’s doing. My little one will purposely do anything to hold Kayden’s attention: He announces what he’s doing in a teasing way and if Kayden continues doing his own thing my little one will try a different approach. We’ve tried to change the approach of this behavior but it’s defaulted setting for my little one, so to speak. If Kayden comes home with a new toy and my little wasn’t given one, he cry’s. If he’s given one but his is blue and Kayden’s is red, my little one will cry for the red one or ask to switch with him. If they’re playing together my little one is the conductor of the activity and doesn’t allow for Kayden to think or do for himself during the activity. If both have their iPads. My little one wants to play on Kayden’s iPad. Or my little one tells Kayden look at what I’m watching. Kayden looks over but returns back to what he was doing. My little one will ask Kayden again to look at what he’s doing. Eventually Kayden will ignore my little one to do what he’s doing independently. My little one will then ask do you want to watch, play or listen to whatever app he mentions. If, IF Kayden happens to say yes, my little one will then dictate the entire event which makes Kayden upset that my little is being so controlling.

It's more of 'Confusion' then 'Jealousy'.
What do I do with this other human that lives with me?
Big Brother is still trying to figure things out.