Percona has a few tools that may be useful
Plan A:
XtraBackup may be the best way to rebuild the dead Master from the good master. (It will take a long time.)
Plan B:
I assume you do not have any slaves of the good master in the location where the dead master is? (You might consider switching to this topology.) You might be able to
1. re-point it to the good master.
2. Use pt-table-checksum and pt-table-sync to discover what was missing and fix it in that one slave.
3. Promote that slave to be the other Master.
4. Worry about rebuilding the other slave(s) of the dead master.
Future:
Another topology to consider is Galera (via Percona or MariaDB). It is multi-master and self-repairing.
The Galera gotchas are discussed here:
http://mysql.rjweb.org/doc.php/galera