Considered a netgate box? I’m assuming “business grade” means he has ethernet (RJ45) on the WAN port?
They do a small pfsense based hardware appliance:
Yeah, its small but for a single user it should be fine.
I’m not sure what the throughput is (However spec lists 200,000 concurrent connections and “exceeding 100 Mbps”), but 100 megabit isn’t something difficult to achieve these days.
Being pfsense, you can scale it up to bigger hardware if required down the track.
edit:
fine print:
“Layer 3 forwarding performance using FreeBSD without a packet filter exceeds 400Mbps. Using pfSense with the default ruleset offers performance exceeding 100Mbps.”
The default ruleset would be NAT outbound, maintain state and block inbound. For home use he might need a little bit more than that but not heaps i suspect (in terms of rule-set complexity)?
They do offer larger boxes such as the 3100 which imho would be overkill for a single or low number of users home network.