Our rec league required every HC, AC, and any "helpful parent" who was on the field with the kids, go through the ASA background check process. The background check for coaching HS is even more stringent, eliminating some who passed the ASA check.A wise person once told me that the first priority in youth sports is the safety of the kids.
I would think any coach stepping on the field would require some credentials (USSSA/ASA/local municipality, etc.) The minute there was any "shaking " or physical contact in this manner that dude should should have those credentials pulled.
I understand the guy may need help, but safety of those kids come first. Work out the rest afterward.
After 6 years in the world of TB, the only org I've seen require any kind of credential (a background check) is ASA. That was one time, 6 years ago, at a Nationals event. Subsequent ASA/USA events, including State-level tournaments, have not had this requirement, nor has any other org.