Parents have life savings tied in 2 houses, no retirement

My parents are in their late 50s, divorced but still live together, and were frugal all their life, but have little to no understanding of the stock market, 401ks, IRAs, and how to retire on those accounts. While they have no retirement accounts, they have enough for bills and a hefty emergency fund/money in the bank of about 100k.

A few years ago, they bought a 2nd house intending to move there but it didn’t work out (too far, undesirable area). Dad is also traumatized by tenants so renting it out is not an option. They would like to sell so I’m figuring out the best route. Dad wants to sell without an agent to save on fees but not sure how to go about that.

Their primary residence and 2nd house are both valued at 700k, or 1.4M total. No mortgages. They have no other debts. We live in a HCOL city.

Should I tell them to sell the 2nd house and put all the money into their IRAs, 401ks, and taxable accounts? They’ll want to retire in 7-9 years.

What should I tell them to do with 700k, essentially?

They also don’t want to move away from the city but are open to living in a new house i.e., sell the 2nd house and buy a new one for a similar price, then sell their primary.

Would appreciate any advice!