Unfortunately, one of the problems with not updating a site with the latest versions of WordPress, plugins, and themes is it leaves the site open to hacking.
Usually, hacks do not involve the database, but it sounds it is possible the DB has been hacked since you can’t login to the admin. The site should be re-installed from scratch.
If the admin password has been hacked, then you could try the standard WP “forgot password” password recovery to see if you can reset it. Then you can do the normal sequence of restoring a site.
There should be information on restoring a site to be found via Google, but try this sequence at the least. This assumes you figure out how to get access to the admin again.
- From cPanel, download a copy of your database.
- Reinstall WordPress – be sure to update to the latest version (4.7.2)
- Reinstall all the plugins.
- Reinstall the latest version of Weaver II – it can be found on the https://weavertheme.com/download page. All versions of Weaver II are settings compatible. I’m not sure what to do about your child theme. I may have been hacked, but probably not.
- The site should be back to working now.
- Install WordFence and let it scan all your files.
- Keep WordFence active, enable its protection measures, and keep the latest updates installed.
Be sure you keep regular backups of the site so it can be restored if this happens again.