I don’t know what are the options the domain registrar uses, maybe it is in the option add name servers, maybe add custom name servers but your client must:
Delete the 4 current name servers:
ns1.f5clouddns.com
ns2.f5clouddns.com
ns3.aztecaservicios.mx
ns4.aztecaservicios.mx
Add the new name servers pointing to your server’s ip.
ns1.aztecahonduras.com 89.116.49.244
ns2.aztecahonduras.com 89.116.49.244
If your client doesn’t know how to add the new name servers, they should ask directly to the domain registrar support.