Most brokerage houses should have a stable value fund that invests in short-term financial instruments.
However, "Stable Value" funds are not all alike, as my brother found out in the last recession. He lost more than 20% in his "Stable Value" fund at Schwab, before he realized it and sold. The fund invested in some high-yield harebrained subprime deals, if I remember correctly.
He was busy with his work and did not look at his accounts everyday like I do. Even when I was RV'ing into the boondocks, I made a point of checking all my accounts online at least every 3 or 4 days.