Vinny has siblings?

I didn’t know JSFV was a thing until recently so I’m catching up on it (I’m so sorry, I live under a rock haha), and after the murder mystery prank in season five Vinny said he texted his sister?

With the way mommy is in love with him I thought he was an only child. Apparently he has two of them. Were they ever in the original Jersey shore? I’m just so confused lol maybe I’m just too distracted by the emotionally incestuous mommy and Uncle Nino and his creepy shenanigans