Can civilian pilots help find missing persons?
Do you mean civilian as opposed to military or private pilots as opposed commercial pilots in a SAR/Medevac role?
A great deal of SAR work is the bastion of non-military organisations and carried out exceptionally well by appropriately qualifed commercial pilots with no military experience at all.
My view is do what can be done to save someone, but do not do something beyond your experience level.
So, as a private pilot, flying around terrain with which you are familiar, spotting someone lost and landing in a safe area and then flying them out is fine. Even better if the private aircraft owner is happy to do that for free.
Anybody creating additional risk for themselves or others so they can be a hero should stay at home and watch it on TV. Not suggesting that was the case here though.
GP