Sigh...well, here we go.
What is the work?
Get Out, the directorial debut of Jordan Peele about photographer Chris Washington going with his girlfriend Rose to meet her parents; while there, he notices some odd things going on with the family's hired help. Soon, he uncovers the truth.
Okay, before you ask, Rose is not going anywhere. She fits snuggly in a nasty niche in the overall brain transferring scheme with luring victims, gaslighting them, and then even after everything is considered, she tries to find more victims anyway. And she was pretty much already evil to begin with. So, she can stay. With that being said, here's her grandad.
Who is he? What has he done?
Roman Armitage is the patriarch of the Armitage family who once starred in the Olympics only to lose to Jesse Owens. Something that he never got over. Due to his prejudices, he came up with a horrid scheme: merging the brain of a white person with the body of an African American due to the assumption that their genetics made them perfect candidates for brain transferring. So, Roman founds the Order of the Coagula pretty much being the reason for every single atrocity that happens throughout the film.
He arranges for his son to become a neurosurgeon in order to perfect the brain transplantation. He later marries Missy, and, with her knowledge of hypnotism, they were finally able to perfect a process. Roman seemingly dies at that point in time, but it actually turns out that he successfully merged with a nameless man and secretly worked as the groundskeeper to stave off suspicion.
Following Chris's escape and the deaths of his and Rose's family, Rose orders her grandfather to attack Chris which he does...whilst completely ignoring the fact that his wife was dead (she was in the car with Chris and had died along with her vessel when the car struck a tree) saying how he had finally beaten Jesse Owens. With quick thinking on his part, Chris snaps a picture of the groundskeeper thus causing Roman to temporarily lose control of his vessel. After mortally wounding Rose, the groundskeeper turns the gun on himself to be taken out of his misery.
Freudian Excuse? Mitigating factors?
None; he was just an old racist prick who never got over the fact that he lost to a black man. With his family, much like Rose, he never shows any affection for them rather using them as pawns for his pseudo-immortality scheme. Also like his granddaughter, he saw his wife's corpse while attacking Chris, but he does not express any grief towards it rather focusing on attacking Chris. He does ask Chris if his granddaughter was a doggone keeper in a weird way, but that's more him just playing along to keep Chris from becoming suspicious than anything.
While he has a minimalistic role, we have a full monologue from him in the video Chris was made to watch as a means of explaining the impending procedure he would be subjected to. From there, we have more than enough to make out what his motivations and personality are showing him as being nothing more than a despicable piece of human filth.
As I have said, each family member has their own niche in the operation with Rose's standing out as being more personable and she was going to continue selecting victims even when it would not benefit her. So, naturally speaking, no need to compare her to her grandfather. Roman is ultimately the one responsible for the despicable operation and condemning blacks to the Sunken Place.