The Stingy Sailor also has a detailed description of refinishing a swing keel on a Catalina 22.
https://stingysailor.com/2015/03/21/refinish-your-swing-keel-for-best-performance-part-1-removing-2/
What worries me is this keel appears to have more than just rust as it problems. Your second photo shows where the cable should attached to a fitting threaded into the keel. I don't see the cable or the fitting and the keel appears to be supported by a length of wire reinforced vinyl hose (like the hose connected to the cockpit drains). This is a critical fitting and would need to be repaired. If the bracket or the cable fail while the keel is raised the 600 pound cast iron keel would drop unsupported to stop when the head of the keel impacts the inside of the hull's keel trunk, possibly cracking the fiberglass.
Your third picture shows a metal plate bolted to the head of the keel (with one bolt missing). This is not part of the original keel. The first picture appears to show a makeshift hanger for the brass support rod that passes through a hole in the keel head. This rod is normally up inside the keel trunk supported supported by 2 plates that bolt into the hull. The second section of Stingy Sailor's article (cleaning) has pictures showing how these parts of the keel should look.
It appears to me that this keel has had major damage with makeshift repairs. I would pass this one by. At a minimum I'd want to have the keel removed for inspection as well as inspecting the hull's keel trunk.
The Catalina 22 is a fine boat.. I've enjoyed mine considerably. Good Luck.
Jack Woodside