I would hope you have a reasonable repair to ride through another year.

Yes, there are/were shortages of parts from the east, that affected many AC factories as I heard from in Merida Mexico,

But that has almost cleared through the system, although with demand...its still an issue.

Ive found, in General, $6-$12K is a range, depending on much.

Speaking only in Florida, and having done 3 AC units in the last couple years, that a variable speed high end unit worked for my home.
Costco ran a $13K system for $8K, and balanced Electric went from $350 to $150 for home, and AC in Flortida,

In MD, your season isnt as long, so you may not want an expensive unit...

I hope its a small repair bill, and if possible or needed, a second opinion....

Good Luck and health for Dad.