IRAs are individual accounts. Form 8606 applies only to one individual. Only her IRA balance and her basis in nondeductible traditional IRA contributions is taken into account when determining the taxable amount of a distribution or Roth conversion from her traditional IRA, calculated on her Form 8606.
If she has basis in nondeductible traditional IRA contributions, a Form 8606 for her was required to be filed each year she made such contributions. If she has no basis in nondeductible traditional IRA contributions, the entire distribution or Roth conversion is taxable.
Your own nondeductible traditional IRA contributions would have been reported on your own Forms 8606.
