Not a lot
"I know not to say it to them," Jeremy insisted, the composed air vanishing in a second, replaced with childish petulance. Obviously you didn't walk up to people and ask if they were worthwhile to their faces, though he suspected calling the wrong types 'not worthwhile' to the right types was perfectly fine. Honestly, it was like Nathaniel thought he was an idiot, like they hadn't had the same etiquette tutors and learnt all the same things. "In case you haven't noticed, they aren't here," he pointed out snappishly. He knew how to behave properly when he was out, or when he was with Uncle Alexander. He just didn't need to apply that to Nathaniel and mother. And why should he, given the way they behaved towards him? Nathaniel treated him like a baby, and mother played favourites all the time. It was always 'Nathaniel this, Nathaniel that,' even when he wasn't here.
Nathaniel's advice, such as it was, was not worth a great deal. Avoid the Pecaris. Well, obviously. Of course, even Pecari had the occasional person worth knowing but they were the exception rather than the rule. It could be assumed one ought to avoid Pecaris unless it was specifically pointed out otherwise, like the girl Nathaniel had photographed the previous year. Speaking of which...
"I look forward to it," he commented when Nathaniel said he would show his photographs. Jeremy managed a degree of sincerity here because he had one to give. Nathaniel could be rather dull as a photographer, sometimes focussing on the most mundane of details, such as particular little flowers that he found extra fascinating and presumably thought was ever so artistic to photograph close up. But Jeremy was still hungry for any glimpse into that secret world, the one he was currently excluded from. There were usually quite a lot of landscapes, ones that gave him a real sense of the place, and sometimes, best and rarest of all, shots of his future classmates. It was worth faking an interest in the odd floral shot, and listening to mother gushing over Nathaniel’s supposed talent, to reap those rewards.
"Really good," Jeremy nodded, when Nathaniel asked about things at home. He sort of suspected that Nathaniel really meant 'how is mother?' but his brother wrote enough boring letters home and got lengthy enough replies from their mother that he knew the answer to that well enough. Probably better than Jeremy did. In fact, mother had had a fierce spell of headaches and withdrawal earlier in the year, but Jeremy was disinclined to act as such a sensitive barometre to her moods as Nathaniel was. In his mind, she was always like that. Maybe to a greater or lesser extend sometimes but.mother having weepy episodes was scarcely news. Jeremy was a much more interesting subject - at least, Jeremy thought so. "I shaved two centimetres off my dive pull out. Coach says I could play for the state junior team if I wasn't off to school. Uncle Alexander was pleased about that," Jeremy said proudly. Pleasing Uncle Alexander was about the highest honour he could imagine. He had said the words 'very good' and given Jeremy one of those curt little nods that showed he had really listened and meant it. "Do you have any Quidditch team photos?" he added eagerly.