Hi Omphile,
Ugh, I'm so sorry to hear that this has happened to you!
Unfortunately, /var/lib/autobackup is not something that is a part of AtoM. It's possible that you have some additional utility installed on your server that performs automated backups. If so, and there is a copy of the MySQL database stored there, then the process to load the sqldump would be the same as found in our upgrades documentation - see steps 3 and 4 here:
You would also want to run the sql-upgrade task (described in the next section of the docs linked above) after loading any backups.
Note that if you have digital objects, which are normally stored in AtoM's uploads directory, you would need a copy of those as well. The instructions for loading those can also be found on the same page linked above.
I would also recommend that you try to find out more about what utility this autobackup is, and see if you can find some documentation for how it works.
Good luck!