As usual, Tony's mouth was open and ready to run off, but ran into a problem gaining traction. There were about nine hundred and eighty things he could say to that, but he couldn't begin narrowing it down until he knew what kind of advice Pietro really meant he wanted. If it was 'congratulations, good for you, go get 'em tiger', that was easy enough and everyone could pretend life was swell. Like hell Pietro needed anyone to tell him that, though.
Conspiratorially, the most neutral reaction Tony could come up with was, "Does she know?" If she did, she could provide Pietro with all the advice in the world on how to propose, how to throw a wedding, and how to be a fine husband to her into her old age. Where Tony came into any of this still wasn't clear, and was clouding his ability to work out what that feeling was in his gut.