Hello Kataroek,
We have a plugin called Community Tickets that will allow your client to create events on the front end. It basically takes the admin editor and places it on the front end so that anyone can submit an event to The Events Calendar without logging into WordPress.
Events Calendar PRO also includes custom fields for events. You can set up as many custom fields as you would like for events.
It’s certainly possible that ACF fields will work for events as well, but it might require some custom development to get it working just right.
Does this help answer your question? Please let me know. 🙂
Cheers,
Geoff