What would help my rotater cuff muscles become healthy again?

This sort of situation is often a result of overuse and inflammation of the fluids of the bursa that lubricate between the tendons running across the bones. From your request to help strengthen the muscles, it sounds as if you've either lost some conditioning of the muscles or had surgery on the area.

However, the most common problem is a form of tendonitis around the rotator cuff.

If you have addressed the inflammation that causes rotator cuff tendinitis, then begin strengthening the muscles by holding a can of beans in each hand by your side and raise your arms so that they are horizontal.

Alternate lifts between those out in front and those to the side for a minute or so, rest and repeat up to 5 times to begin with. For any exercise to help, you should perform it at least 3 times a week.

I hope it helps

Best wishes

Earle