Like you, I don’t know the exact timing. It could be that who ever asked the question ‘got inside’ the military notification channel times, i.e. the questioner saw a flash news report. Or the President got it and issued his tweet, which I consider appropriate. I don’t expect a tweet of condolences to include specifics about what happened.
Here is what is not in the Breitbart article excerpt posted:
“Trump later, after receiving more information on it, tweeted that he hopes for the best for the lost sailors. The collision left 10 sailors missing and another five injured.”
““That’s too bad,” Trump said when responding to shouted press questions about the collision of the USS John McCain with an oil tanker, per a White House pool report earlier in the evening.”
It sounds like that the President’s original comment was based upon the shouted question, without him knowing anything else about the accident. Thus those tweeting his original comment to a reporter is another ‘cheap shot’ by the anti-Trump crowd.
5:24 local time
http://www.telegraph.co.uk/news/2017/08/20/rescue-efforts-launched-us-warship-collides-merchant-vessel/