It has great hardware and was king back in 2015/2016 when tested, but it has been surpassed.
How big in SqFt is your friend's home? What is his ISP paid for speeds? Fibre, cable, DSL? How many devices are normally connected wirelessly?
What is the construction of the home? Concrete? Drywall? Plaster/lathe?
What other features might he need besides WiFi coverage?
What is his budget?
Will the router be placed centrally in the area to be covered, or, will it be off in one corner and/or a basement?
The Asus RT-AX88U with RMerlin firmware and built-in amtm support for additional scripts/capabilities for the router is easily the top choice right now. With more scripting options becoming available almost every day. The link below is for the RMerlin firmware and the models supported.
https://www.asuswrt-merlin.net/features
https://www.asuswrt-merlin.net/about
The link below shows what amtm can bring to the router in a very accessible format.
https://diversion.ch/amtm.html
A supported Asus router with RMerlin firmware and a spare USB drive for amtm, a swap file and available scripts are very hard to be surpassed in the level of security, performance, and the easy customization possible.