Sure. The Jojo manga has been translated into English and is accessible in many bookstores and digital stores. Some versions might have differences in translation quality, but you'll have options to choose from.
There are several Jojo manga series that have been translated into English. Some of the popular ones include 'JoJo's Bizarre Adventure: Phantom Blood', 'JoJo's Bizarre Adventure: Battle Tendency', and 'JoJo's Bizarre Adventure: Stardust Crusaders'.
Sure, JoJo Part 7 manga is available in English. But the availability might vary depending on where you look. Some physical bookstores or online platforms might have it in stock.
There's no way to really tell if it's common specifically for someone named Jojo. However, in general, reading fanfiction is a popular activity among fans of many different franchises. The Jojo series has a large and dedicated fan base, so it's likely that there are fans named Jojo who partake in reading fanfiction, but we can't say for sure how common it is without more data.
Perhaps this Jojo is interested in exploring different interpretations and stories within the Jojo universe that fans have come up with. Fanfiction often takes the existing characters, settings, etc. from the original Jojo series and creates new and unique storylines. So, this Jojo might be a big fan of the series and wants to see what other fans have imagined.