This was almost exactly the situation my mom was in at age 77 albeit more money but no family business. The LTC insurance benefits for five years were a game changer. That $1m could easily turn into closer to $1.5 left alone with reinvestment in five years
Here’s how I/we looked at it. She’s not gonna run out of money if she lives to be 130. The investment approach was income was hers and assets were for heirs. Some munis, some income funds and a large amount of blue chip dividend stocks with goal of 3-4% income on those stocks. You should be able to generate close to 40k income which you reinvest while ltc insurance pays the bills. If that runs out you can take dividends as income.
Honestly 20-50k is a lot on top of SS and ltc insurance and will go down as she is less able or willing to do things. The big expense will come toward the end if she goes slowly like mine. Couldn’t do assisted living and needed more care/attention. Spent 18 months in a private long term care room which was more than 2x what assisted was. I airways said if she saw the checks I wrote each month she would check out on the spot. But it was her money and she could both afford and deserved the best. None of us needed her money but once she was gone it did make a big difference to my sister’s retirement. With that said nearly two years later not a penny has been spent by any of her four children