Oh good grief - my sympathies to your sons.
I raised 4 boys and - we had rules and they were taught caution, but allowed to be CHILDREN - and if they got hurt, they didn’t get punished for it.
Of course, my sons weren’t kept on a leash. They had fun, but as you said, they were taught caution.
Maybe I didn’t express it well. In my neighborhood, I saw all kinds of dangerous things going on. Kids building ramps and jumping their bikes off them. Skate boarding, roller blading IN TRAFFIC without any head or other protection.
Not only climbing trees, but seeing who could jump out of them from the highest branch.
And this was going on with their parents in the house/yard.
All of us pay when parents are negligent.
He has got to help subsidize those illegal aliens and other “deadbeats” out there. You know, his unfair share.