There is a brief mention of this meeting in H.W. Brands book, "The Man Who Saved the Union". Right off the bat in the first paragraph, "His ancestor Matthew Grant crossed the Atlantic from England with the Puritans in the 1630s, and subsequent Grants migrated progressively west: to Connecticut in the seventeenth century, Pennsylvania in the eighteenth, Ohio in the nineteenth. Jesse Grant, of the sixth generation of American Grants, for a time lived in Deerfield, Ohio, with a family named Brown, of whom a son, John, would attempt to start a slave revolt at Harpers Ferry, Virginia, in 1859." p. 7, Brands.
On p. 81 of the same book, Brands states, "The abolitionists rejoined with reinforcements of their own, including the monomaniacal John Brown. After crossing paths with Grants father in Ohio, Brown went east to school, then into business and farming."