There are quite a lot of problems in this episode. First, all the child actors are horrible. You can see them looking off camera, not paying attention, and generally being awful. Plenty of child actors can actually act and focus on what's happening in the scene. Maybe these kids were too young.
The major problem in the episode are several plot holes that are never filled in. The parents not knowing that their son wasn't in Mexico is beyond ridiculous. They had to have known the grandfather wanted him and they certainly knew he had just supposedly shot his father. Your son has just gone through a traumatic experience and you send him away with some strange woman and then don't even track him to make sure he got there? Couldn't one of them taken him themselves or at least traveled with him to ensure he got there? The script gave us some lame story about how the grandfather was going to send a wire saying he had arrived safely. It didn't fit with what we know about David's mother and stepfather.
The other glaring plot hole was when the Beverly Hillbillies lady claims everyone was telling David the shooting was all a bad dream. She hoped some day he would believe it. Unless his father was planning on coming back from the dead, why would any of them think this was even possible? I realize he's a young kid, but lying to him about his father isn't going to help him get through it. Particularly since he'll never see him again. A very lame plot point that made little sense.
This episode moves the kid around like a chess piece. "Come on David. Come with me David." The kid seemed totally unconcerned that he was with a strange lady instead of his mother. Considering he had witnessed a lot of emotional scenes with his father, it seems unrealistic that a 5-yr old wouldn't be crying for his mother. He seems willing to go along with anyone who wants him so long as they watch him wiggle his ears.
Considering a murder case generally takes months to prepare, how was it that Dick Benedict's jaw was still wired shut all that time? The actor kept rubbing his jaw while testifying as though he was still in pain. Very unlikely for an injury that had to have been several months old by that point.
The way that restaurant punching scene happened was so ham handed and poorly directed. First of all, Selkirk was sitting within clear view of Claire. How could she not have seen him? He had to knock her boyfriend out before she noticed him. And even that scene was ridiculous. Claire's boyfriend was tripped and then allowed another man to hold him while a second man punched him. No man would allow himself to be manhandled like that. I realize he fell on the floor, but he hadn' t hit his head so there was no reason he should have stood still to have his jaw broken. Again, very ham handed. That's a directing issue.