For a short while James was like this, I do believe there is an element of it in all 2 year olds, and that some are more bloody minded than others. Obviously 2 boys before you know what to expect almost, but then there is individual personalities too mixed in and as we know, we are all so so different. My sister and I are like chalk and cheese. When my brother was small he used to pass out with temper - pure temper!! He is lovely now though.......but you wouldn't cross him lol!
Anyhow, what am I trying to say? So damn hard in text......when they start acting in certain ways, it is easy to end up being swept along with it for ease (obviously!!) but once on your 3rd even more so because you have 2 others to consider too so make life as easy as possible short term, OBVIOUSLY!!! Maybe a lot of it with Luka has become a routine you have all got caught up in because of his responses, a lot of them being normal 2 year old things, the youngest, his personality etc etc. So when he screams you change to stop him, or always make allowances so you never reach that stage with him. Or you don't allow him to get to the stage of having an absolute fit so he thinks all is ok and sometimes they need to have the screaming fit a few times.....maybe lol. My Ds has funny quirks, he will NOT have his sleeves rolled up to the point of screaming, he cannot stand water being poured over him (so he has a bath about once a week as it is so bloody irritating) but he screams the place down.....like I am killing him, I mean it, it is horrific, like I am pouring boiling water on him I still carry on mind when I do it. He is very very particular and I think that is just his personality, not Autistic or anything. He also will only have his trousers below his waist and things like that, but it is easier for me, I only have one so have more time to let him rant things out if needbe, it is much harder to do that once you get beyond one, but it is still weraing......toddlers are the little darlings. Just recently, I have felt like leaving james parked up in a shop somewhere.
Jan made interesting point about nursery - they obviously have no major concerns with him, but they would be a really good place to ask about him as with none of you there, how he actually reacts. i also think with the slower talkers, they are more in their own world, for obvious reasons.
I hope I don't come across as all "it's this it's that" etc, am genuinely concerned for you. Big hug.x