He's the Eldest child.... among 2 girl sisters.
Boys are also very physical and active.
They are not like girls.
Your son also shows perhaps some frustrations with being the Eldest... and him having to be so 'perfect' and understanding and patient and on eggshells... around the younger ones... when he too is still just a child. A young child. He needs leeway and age appropriate 'expectations' upon him.
When I had my 2nd child... I explained to my Eldest child, all about baby/child development... in simple terms she could understand... so that, "she" could understand... that it is not "her" that is "wrong" ...but that a baby is not like her, cannot do things like her, cannot talk like her, cannot understand like her, and that they DO cry and wake and need Mommy... but that being so perfect and understanding is not her 'job'... but MOMMY's job... to care for her little brother. For my Daughter, explaining and talking WITH her about these things... helped a TON. And if made her feel "special" and that it was a 'bonding' thing between us... with her as the "big sister" and that I trusted her enough to talk with her about these things.
The thing is... and Eldest child has TONS of "expectations" upon them.... but it does not mean they "can" do it or do it accurately nor articulately. And it does not mean that the 'expectations' are age-appropriate... it is just what the parents expect. And, carrying that burden of 'expectations' can be a big load for their tiny shoulders....
Naturally, when another sibling is always crying... a young child can't tolerate that.... so then they don't want anything to do with the baby. They get frustrated and tired of it. Adults do to.
An Eldest child, cannot be all 'perfect' and doting. Its okay.
Have things for them that have nothing to do with the younger one's. His own time, his own activities, his own routines.... his own time away from them even, his own play-dates etc.
You feel tired of it, and his inability to do everything perfectly... but well, he is tired of it too and being 'expected' to know everything, right now.
He is only 4. He is the oldest child... but that does not mean he can, developmentally or emotionally.... do everything that well.
At this age, their emotions are not even fully developed... and they are still very young... to have full maturity and the full range of cognition and how to handle situations... and their siblings.
Also, your son just seems irked... with the whole thing and as you say he is just "doing it to make them upset...."
Instead of making "him" the "problem".... try teaching him about "family" what family is, what "teamwork" is, how he can help you, how he is your first "baby" and you love him for that.... that YOU have 'changed' too because you are a busy Mommy with other kids...but that he is important to you... and you trust him.
Help him, to express himself, good or bad and even if he is irritated that he can tell you that... and seek solace from you. Not just get scolded or 'corrected' for everything he does or feels.
He is a boy.... and boys NEED to learn how to express themselves... and know that it is okay...and that Mommy is there for them, too.
Teach him about what a 'sibling' is... what family is... what caring is... what you ALL are as a 'team' and it is not just "him" against his siblings... and being the odd-man out.
He may just feel ousted and the minority there.
all the best,
Susan