If your parents charge interest, they must report the interest they received as taxable income. If you make fixed payments, there are various web sites that can calculate an amortization schedule (how much of each payment is interest vs premium). If you make variable payments, there are other ways to calculate the interest portion of each payment.
If your parents don't charge interest, they must still report the interest they could have charged as taxable income. This is called imputed interest. They must use at least the applicable federal minimum rate. (The federal minimum rate for a long term loan made in November 2022 is 3.85%.). This rule is because the IRS expects taxpayers to conduct their affairs in a businesslike manner.
The principal portion of the payments is not taxable income, because it is just a your mother's money returning to her.
If your agreement was that payments would not start until some time in 2023, it is not necessary for your parents to report any imputed interest on their 2022 tax return.
You do not need to issue a 1099-INT or any other documents to your parents for the interest you pay, because the loan was not made in the course of a business or trade. (If you borrowed money to start a business, you would issue a 1099, but since this was to pay off personal debts, you don't issue a 1099.)
