Nick does have a Poshmark account, and it's been active this month.
For those not familiar with Poshmark: it's a platform that allows individual sellers to resell new, used, vintage, etc. clothing. It's pretty easy to use, and you can cash in your earnings or use them for credit in the app itself. There's a web interface, but it's really more of an app-based thing. In the very beginning, it was women's clothing only, but it's long since expanded to include children's clothes, men's clothes, and household items. It's a massive platform, and you can really find anything and everything-- random vintage items, last year's blogger-favorite dress, a plain black all-occasion dress.
There's not much to see about Nick's account. You can see what users are selling (if anything), since that's the whole point of the app, but you can't see what they've
purchased unless they leave what the platform calls a "love note" (a seller review). Nick, unsurprisingly, has not left any of these. I can't definitely tell if he's purchased anything, because the app just doesn't work like that.
Don't take any notice of who's following these users. The app actively encourages you to follow as many people as possible and to share as many listings as possible, so new closets in particular can easily gain a lot of followers. If you're a seller, this is good for the algorithm and thus good for your resale business.
Here's his account (
link):
Specifically, he joined this month:
His "recent brands" would be brands recently purchased or browsed. I don't buy or sell menswear and am not familiar with Via Veneto, but here are the first few listings that came up when I tabbed over to the brand:

His mom also has an account:
However, hers is older and long-abandoned:
If Kayla has one, she didn't use her real name-- I got no results for her. She'd do well to spend her empty days photographing items and creating listings.
He could also be using Depop, but I'm less familiar with that platform and haven't checked it.