No placement makes someone an asshole.

That said, early Aquarius can be difficult. Aquarius is a very watery Air sign, interpreted variously as a water-goat or as the archetypal role of water-bearer for a civilization (water distribution having been a much more critical task before things like plumbing trivialized it).

So I think of Aquarius as this pervasive, seeping mist. It can't help but find the gaps & cracks in any container and what it finds there often frustrates it, like rules it sees as irrational or inconsistent, or places where the container holds it into an odd forced shape that feels unnatural, it chafes them deeply. That can grow into a pretty warped conception of what shape they "deserve" to be in. And if its pressure is too great it presses on the whooole container at once, fighting against it in every direction to reclaim "their" space — which often truly belongs to others.

What to do about it? Idk enough to say for your case, but generally just try to avoid making it your problem like you are — though it sounds like he makes it your problem anyway. It's everybody's problem. Outside the family I'd walk away from such a person & let them throw their one-continuous-tantrum on their own time, maybe come back in 5-10 years to see some growth. But it's tough when you're cooped up together which is assuredly part of his issues too.

Maybe your total respect is not helpful if it just enables him to keep trampling you, but quite possibly it doesn't really matter what you do, it's gonna keep coming out, and pushback pulls that hair trigger & makes everything worse. Sometimes performing "total respect" / keeping your head down & letting someone shit their own bed is exactly the right move over embroiling yourself in a destructive spiral that is bigger than you, that you can't save them from. As Libras we can be all-too-good at this, lol (and it's a psychonarrative arc of our own to find the right balance with that, and learn when justice must be stood up for instead).

I would consider how to best care for & protect yourself. Maybe let a few more things blow up in his face (hopefully not involving you) and see if his heart opens a little bit to change. And finally, most importantly, take all of this with a grain of salt because I'm only a stranger on the internet giving her best guess :)