Contributions to retirement accounts, ROTH or otherwise are based on "EARNED" income. If you "give" your MIL the money, she didn't earn it and therefore can't count it towards a retirement contribution. If she provided daycare in your home, then she's a household employee that would would need to do paperwork for, as well as withhold and pay taxes on the income you pay her, and issue her a W-2. You'll need professional help for that, especially if your state taxes personal income as that will more than double your paperwork.
Otherwise, if you issue her a 1099-MISC with the amount you paid her reported in box 3, she' report that as self-employment income on SCH C as a part of her personal 1040 return. Then it's earned income and she can contribute to a retirement account based on that earned income.
Either way, you have a deadline of Jan 31st to issue the W-2 or 1099-MISC.
