Vintage leather halfbelt repair help

[yankee air pirate]

I am restoring an old horsehide halfbelt jacket and need some help on a repair. At the bottom edge of the back the leather has torn at the seam and seems to be a little weak at the spot so I was wondering on the best method to fix it? I heard that you can back it with another piece of leather with glue, but I thought you shouldn't use glue on vintage jackets. So any help is much welcomed!
Thanks

 

[yankee air pirate]

Problem solved! THANKS to buzzthetower for the great info!