Did you happen to check for up-and-down play in the axle while the drum was off?
If the axle bearing is worn it will cause premature brake failure, usually on the front shoe at the top.
If that's the one that let go, I'd check it ASAP.
P.S. Thanks for getting back with the results.
I know it can get awful we and messy in there after a failure, but check for gear oil on the inside of the tire and the drum. If it's just a bearing and seal it can be replaced before the axle shaft gets scored too badly.