Air France Frequence Plus - Seat Plus question

Apologies if this is an easy one, I'm not at all familiar with AF.

My Brother is flying CDG-GIG shortly. The AF site talks of "seat plus" seats, which look to be closer to the front / exit row seats. EF shows many of these are open.

However, the AF website shows them all as occupied/blocked.

I had got the impression from the AF site that these seats are for purchase, though maybe I am wrong and it's only for elites? Alternatively, is there any facility (beyond buying up to the applicable fare class) to purchase T-24 or less PV seats? I'm trying to do what I can to make his trip a little easier, as CDG-GIG is a hefty ride.

Also, my Brother has been trying to enroll in FB online, but keeps getting 'Were sorry, an unexpected technical error occurred. Please try again later or contact the Air France help desk.' Has anyone else had recent problems?

Thanks in advance.

The Seat Plus are available for purchase at OLCI from 30 hours before your first flight.

There is no facility to upgrade to Premium Voyageur short of possibly upgrading the ticket to the regular PV price (if allowed under the ticket's conditions), which will be typically quite expensive.