I doubt that his status on or off the community watch will have any bearing on the charge of second-degree murder. Even if they'd encouraged him to carry a gun (and apparently they didn't), the issue would still be whether he had sufficient reason under the law to shoot someone with it.

The difference would be important in a civil suit against the community. If the watch program kicked him off, or if they told him explicitly not to carry and he did it anyway, that suit would probably go nowhere.

If they'd encouraged him, it would be very different.