Geoffrey brought his elderly mother with him, and while he did appear as dour and stoic as he usually does, there was a lightness in his eyes that only those closest to him would recognize. He was adamant about not having Bellatrix's scheduled dueling interfere with the wedding of his old school colleague, as celebrations of society families are just as important (if not more so) than that. He was his usual quiet self, but clearly enjoyed himself as he smiled and watched everyone else enjoying themselves. Rather than feel sad about remembering his own wedding, he took happiness in seeing the new couple - and a very efficient couple in society, at that!
Although he was kind of jealous that their seafood theme was much better than the lamb Demeter and him had at their own wedding.
He made small talk and blushed as his mother gushed to Augustus and Rosalind about how this was the most beautiful wedding since the one of her son and his deceased wife, muttering apologies and whisking her off to try to get someone younger to dance with her to take her mind off of it.