Older network card incompatible with Frontier 1Gig internet router?

[UnclKracker]

I was helping a family member set up his laptop for wifi. He had just moved in and signed up with Frontier Fiber for their 1Gig internet service. The laptop is an older HP running Windows 8. He'd had no wifi problems with COX cable. The laptop has been at my house connected to my wifi. My service is also Frontier Fiber only it is a 500mb service. The router uses the coax connection. His Internet service requires a totally different setup than mine. For the 1Gig service, the router requires an ethernet cable run from the ONT. It doesn't use a coax connection.
When I try to connect at the new location on his HP I can see numerous wifi networks available except his. I had brought my own laptop. I can see and connect to his wifi.
I spent almost 2 hours online troubleshooting with Frontier Tech Support which ended up with her recommending I contact HP for support.
She knew of no problems with the 1Gig router that would prevent us from finding his network.
Has anyone run into this? Do you know if there is an incompatibility between some wifi hardware and these 1Gig routers? It bothers me I had to spend 2 hours troubleshooting with Frontier just to be told to contact HP.

My brother-in-law doesn't do much more than browse and email. I found him an inexpensive Laptop that should work fine for his needs.

 

[Bighorn]

Had to look up the acronym for ONT, it's Optical Network Terminal. Maybe some pages here will have help:

ont at DuckDuckGo

DuckDuckGo. Privacy, Simplified.

duckduckgo.com

How old is the computer? Wireless can be problematic with older ones with the adapter, 802.11a, b and g being long out of date, 802.11n is fairly common with 802.11ac or ax being the latest. I haven't any issue with 802.11n on my 802.11ac Router.