Broken brick!

[rebuildinginpa]

I have a row of bricks under my sliders to the front deck. While shoveling snow a few years back I broke one of the end bricks (about 3/4" off top) and have not been able to keep it sealed since. Because it is an end brick, it sits under the doorframe making it (what I would think) very difficult to replace.

Any ideas on getting this sealed permanantly?