He's a good coach.
I think that he knows what he's talking about.
You need to focus on a firm grip, isolation of your trigger finger (so you don't "milk" the gun), and a slow, smooth trigger press. Concentrating on your sight picture should come later.
The brand name of the 1911 doesn't matter. All of them will outshoot you, until you gain a little experience with the techniques the coach and I have referenced.
The only thing that sets one 1911 apart from another, from your point of view, is reliable feeding. But a firm grip at the end of stiff arms takes care of that.
You might give a little thought to what the old, wounded veteran did indeed sacrifice for you. You might therefore accord him somewhat more respect than you seem to find possible.