I'd suggest starting with the retirement predicaments wiki page. Go through all of that. You'll need to gather more information and you'll want to do some reading (I'd especially recommend How to Make Your Money Last by Jane Bryant Quinn), even if you convince your parents to hire a financial planner, it will help you pick an advisor and review what they're doing.

I would worry somewhat less about advanced tax planning, using the right tax-advantaged accounts, etc. and more about your parents simply not saving enough money.

As far as a financial planner goes, what you want is a fee-only CFP. Read the financial advisors wiki for more information. If your father is amenable to the idea, I'd suggest interviewing a few candidates (probably over a video call these days) with you on the call.