slept with his ancestors and

This is a polite way of saying he "died, as his ancestors had, and" (See: rc://en/ta/man/jit/figs-euphemism)

the garden of Uzza

Possible meanings are 1) "the garden that had once belonged to a man named Uzza" or 2) "Uzza Garden." (See: rc://en/ta/man/jit/translate-names)