Why won't Mrs. Younger lend him money to start the business?

First, Mama cites that they aren't business people.... second, she tells Ruth that she won't add selling alcohol to the things she answers for in death.

MAMA: Well—whether they drinks it or not ain’t none of my business. But whether I go into business selling it to ’em is, and I don’t want that on my ledger this late in life. (Stopping suddenly and studying her daughter-in-law) Ruth Younger, what’s the matter with you today? You look like you could fall over right there.