I just replaced a head gasket where coolant was leaking into a cylinder, but I do not use anti-freeze. However, gasket leaks are generally small, and over time just the coolant above the gasket will leak. My engine sat for about 6 months.
In all of my 58 years of playing with car engines, I have never seen anti-freeze harm a bearing, be it babbitt or aluminum. However, I do know that spent anti-freeze turns acidic, so it is possible but not common place that anti-freeze gets into bearings and destroys them.
It has been my observation that a coolant leak into a long period dormant engine cylinder may cause some surface rusting of the cylinder walls, and in an extreme case, some pitting of the cylinder walls.
1. Pull all of the sparks out;
2. Using a flashlight, look into the spark plug holes and see which cylinders are wet with coolant;
3. Put about 1/2-cup of liquid lubricant in each cylinder;
4. With the gasoline OFF and ignition OFF, hand-crank the engine. If a cylinder has a significant amount of coolant in it, the coolant will pump out thru its spark plug hole;
5. Replace the head gasket;
6. Change the crankcase oil;
7. Take the car for a ride long enough to get engine up to operating temperature;
8. Re-torque the cylinder head nuts;
9. For peace of mind, do a compression test.