n, You have two choices...1) remain silent and look ungrateful; or 2) respond in a very courteous and grateful manner. If you do the second choice, just say "thank you for the information" and let it go.
I'm still not convinced that he's not the one that sent the last message. Yes, in the past he's now signed the email, but they do go through a business like attitude during the crisis and sign everything differently. Play along for a bit...if you don't react, the individal will slip up.
Sit quietly, the answers will reveal themselves when you least expect them to. The past is gone, the present is a gift and you need to focus on today, allow the future to reveal itself when it is ready.
