Nope.

Rating: 4/10 (2 November 2019)

Don't get me wrong. This could have been a great movie. The acting is brilliant, the cinematography amazing for this type of movie. It doesn't frighten you with cheap jump-scares, it's more the psychological horror that makes you uncomfortable.
I don't understand the high rating on this movie. Haunting of Hill House got a 9 from me, but definitely not Hereditary.
But I agree with another review beforehand and need to note the following:

You don't send a 13 year old to a high school party with a senior. Nor would you just take your sister without an argument. You also would have an Epi pen on you at all times, if an allergy was THAT severe.

To quote what someone else wrote: "People who just decapitated their sibling in an auto accident don't simply drive home, go to bed, and leave a human head on the ground ... Additionally, when this kind of thing happens, the cops tend to get involved...? In this movie, however, that's exactly what happens and no police, no cleanup and they're driving the car in the very next scene." That. So much that.

"When your son, who has weeks or days earlier killed your daughter, resumes going to school almost immediately, without therapy or counselling, has a seizure and bashes his own face in on the desk, you don't load his lifeless body into the same Volvo, drive him home, and deposit him into his bed - still unconscious - without any kind of medical consultation or observation at all." 100% agreed.

The plot is about....satanists (including the grandma) getting a demon into this world, Paimon? And to give him the appropriate body, the brother has to accidentally kill the possessed child and then inn the end throw himself out of the window and die himself ? That's the twist, really? Not very innovative, and lazy execution with major plotholes.

In the end I felt weird about the entire movie. It wasn't a dumb, scary movie. It started off as a psychological thriller, a drama, and got really strange to the point where I felt weird myself.