An infection...in/of what?

There needs to be more info.

If he got infections ever since the incident, due to being paralyzed by the shooter, and one of these infections eventually killed him...than it's the shooter's fault. But if the infections were/are due to neglect or of a more "natural" or everyday nature...than no, it's not the shooter's fault.

Depends on what the infection was from!

__________________
Minds are like parachutes. They only work when they are open.

~Thomas Dewar~