Investment property proceeds for retiree

[GJinVA]

I'm trying to help my dad out with in issue that just came up. For years he has held the paper on a couple investment properties that he sold when he retired. (That 8% interest looks brilliant now) anyway he is much older now and the owner is selling one of the two properties. He will keep the other and continue to make payments on the property that only amounts to 25% of the old note. This mean my dad ends up with $70k as an 83 y.o. What is the smart thing to do with this money so he can minimize his tax burden?
He can drop $6500 in a Roth IRA, maybe, but that still leave a lot of income

[terran]

IRA contributions require earned income, so that will only be an option if he still works.

[FIKris]

You can earn up to 70,000 in long term capital gains and pay zero tax as long as your dad is in the 15% tax bracket.

The best strategy would be for him to reduce his taxable retirement income to try to stay in the 15% tax bracket the year he sells the investment property.   Do that, no tax on the 70k long term capital gains from the sale of the rental property.