Dawn, if you can swing it, the PI sounds like a good idea (OG didn't nix it!)
I predict that one of the following will happen:
1) Wifey is too scared of going to jail to defy the RO. Dad will show up for a few visits just to "show you" you're not going to keep him from son, but tire of wifey nagging him and flake out.
2) Wifey will behave for a while, until she thinks it's "safe" to try and sneak around the RO, and hopefully get her crazy rear end thrown in the clink!
And there's ALWAYS the hope that dad will grow up and learn to parent his child at least halfway decently, if not well, and maybe even reclaim his private parts and kick crazy wife to the curb!