If he is not a resident of Clark County (as defined) he does not have to register his handgun, let alone carry the "blue card," which is not, and never was, required in any case.
If a board of county commissioners in a county whose population is 400,000 or more has required by ordinance or regulation adopted before June 13, 1989, the registration of a firearm capable of being concealed, the board of county commissioners shall amend such an ordinance or regulation to require:
A period of at least 60 days of residency in the county before registration of such a firearm is required.
A period of at least 72 hours for the registration of a pistol by a resident of the county upon transfer of title to the pistol to the resident by purchase, gift or any other transfer.
IANAL and this is not legal advise.