I think that's essentially what he said to begin with. If the BU doesn't know how to ask for help, then its a lost cause anyway. It sounds like the BU wouldnt have changed his call for anyone.
I had one similar to this recently - BU pretty clearly misses a tag play at 2B (calls safe), I saw an out, def coach saw an out and asks me to change the call. I told him that it wasn't my call and there was no dropped ball or other information I could add to the BU's look. BU did not ask for help....on a straight judgement call there was nothing else I could do, except watch the coach chew on the BU for a sec or two. I'm certainly not going to say, "yeah, coach, he blew it, tough cookies for you!"
Later on, this BU blew a pulled foot at 1B, but in that case he asked for help, I told him the foot was pulled, and he reversed his call.