What do we learn about the Grapes’ past?

From the text:

Momma was an only child and her mother died when she was a little girl. My other grandpa, Lawrence Grape, drank himself to death; this happened before I was born. Apparently he was mean and bitter. He had two boys — my dad, Albert Lawrence, and Gilbert Palmer Grape. Gilbert Palmer died in World War II. He was shot down in a plane and he's buried with the other Grapes, about four graves from my dad. It seems my other grandmother, Dottie Grape, blasted my mom and dad for not naming Larry after Gilbert Palmer. So when I came along, the family was in ecstasy, because they could appease my Grandma Dottie, who lived alone in Alden, Iowa. Grandma Dottie has lived, if that's what you'd call it, in a nursing home for the last eight or nine years. She's forgotten everything and everyone. My mother despises her and the only memory any of us has of her is how when she'd blow smoke in our faces, we'd cough, and she'd just blow some more. For all practical purposes. Grandma Dottie is dead. We have no aunts, uncles or cousins.

Understand that my father was the soloist in the choir of the Endora Lutheran church for many years. And while he was the worst singer ever, he was the only one with sufficient courage to go it alone. When he tied the knot in his neck it came as quite a shock. Dad hung himself on a Tuesday and was buried on that Thursday, and by Sunday, pregnant Momma, Amy, Larry, Janice, me, and a baby Arnie were back in church, sitting in the front row.