This isn’t your standard cookie-baking, nursery-rhyme reciting, warm-hug giving grandma. Richard’s Granny has probably never baked a cookie in her life, and we’re pretty sure she’d say that nursery rhymes were the devil’s work. She’s hot-tempered, illiterate, crazy religious, and convinced that books are going to let the demons in. When she catches Ella reading to Richard, she calls her an "evil gal" and shouts that she doesn’t want any of that "Devil stuff" in her house (1.2.24).
Basically, Granny stands in Richard’s way at every turn. She won’t let him have books; he has to sneak them into the house. She won’t let him have a job; he has to actually pack his suitcase before she agrees. He wants to go to school and get an education; she doesn’t even try to make sure he has clothes to wear. Probably the only reason why Richard hasn’t threatened to cut her the way he’s threatened to cut everyone else is that even he knows it’s considered pretty crazy to try and hurt your dear old grandma.
Oh, but she does care about one thing: saving his eternal soul from entering "the precincts of sin" (1.4.99). Here’s some free advice, Granny: don’t hold your breath on that one.
Granny does have two unintentional and positive impacts on Richard’s life. The first is that she looks white, and that makes Richard wonder what this race thing is all about. As Richard says, "It might have been that my tardiness in learning to sense white people as ‘white’ people came from the fact that many of my relatives were ‘white’-looking people. My grandmother, who was white as any ‘white’ person, had never looked ‘white’ to me" (1.1.256).
The second thing is, she gets him to write his first short story. True, what she really made him do was pray in his room, and praying turned into writing hymns, and writing hymns turned into his short story, but does it really matter how he got there? The point is, if Granny didn’t make him spend time alone in his room just thinking, he might never have picked up a pen to begin with.