If the country where you live isn't included in the banned list of the particular gambling site, you should have no issues accessing that site. However, since you mentioned that there are some religious concerns on gambling and it is very much possible that the government had ban those domain names. If this is the case, switching the ISP will not help either because it's banned on the country level. The only way to access those sites is via VPN.
It's possible he's from a conservative Islamic region where gambling is considered Haram/sin. There is no problem with that as it is a majority-rule voting system, but he must follow the rules and refrain from gambling, there is no pleading for mercy in those areas, I've learned.
My opinion is that if you don't want to use a VPN on gambling webs, you should use Tor instead of a VPN since a VPN connects you to a single server, but Tor allows you to connect to a large number of nodes in various locations, and they are not just nodes, they are decentralized nodes with multiple layer encryption.