Teacher, Moses said, 'If a man dies

The religious leaders were asking Jesus about what Moses had written in the scriptures. If your language does not allow quotes within quotes, this could be stated as an indirect quote. AT: "Teacher, Moses said that if a man dies" (See: rc://en/ta/man/translate/figs-quotesinquotes and rc://en/ta/man/translate/figs-quotations)

his brother ... his wife ... his brother

Here "his" refers to the dead man.