Why does he need to cancel his hospital operation? There's no need for him to stay in the US until you have your visa - he can fly home at any time, as long as you don't enter the UK before he does. If he needs to fly home for any reason, then he can fly home.
People who applied with priority at the beginning of July got their visas 1-2 weeks ago, so going by their timelines, I would imagine you'll get yours in the next couple of weeks.
Also, at least one of those people did not get an acknowledgement email from UKVI, so just because you haven't received one, it doesn't mean your application hasn't been opened yet. It may just be that your email got missed but that it is moving through the line along with all the others.
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