I assume those users will then be unable to receive their DHCP leases once the service is deactivated. But, those users won’t ever be part of the domain.
DHCP operates on OSI Layer 2 and has no special relationship with an Active Directory domain or its servers. As long as your wireless clients have layer 2 connectivity to the same network where your DHCP server will run, they'll be able to get leases from it.
It's common for AD Domain Controllers (DCs) to offer DHCP services on the network, but it's by no means required.
It doesn't matter if your router or DC host DHCP, even if you have a mix of domain and non-domain clients. However, what does matter is the DNS settings delivered by your DHCP server.
Non-domain clients need a DNS server that can resolve Internet host names. In addition to this domain-joined clients need a DNS server that can resolve domain-specific DNS lookups. Domain-joined machines use DNS to locate services offered by the domain, such as authentication, time synchronization, etc.
In a typical configuration, your DC also acts as a "Active Directory integrated" DNS server. This means it can resolve the domain-specific queries needed by domain members. If this DNS server is configured with root hints or a DNS Forwarder, it can also resolve hostnames on the public Internet.
Now, if you choose to have your DC act as your DHCP server, it would point all DHCP clients to the DC's DNS server. And everything would work. Domain clients would be able to resolve AD-specific queries, and domain and non-domain clients could resolve Internet hosts too.
If instead you want your router to be the DHCP server, you would want to configure it to point DNS to your DC's DNS server. And everything would also work just fine.
Technically you could use separate DNS servers for domain and non-domain clients. But unless you're doing that by configuring settings manually on clients, that's a lot of unnecessary trouble.
Note: This answer assumes your DC is on the same IP subnetwork as the rest of your devices and that you only have one such subnetwork.