If that is the case then, when booking seats, inform them that airport assistance will be needed. I may be wrong but I'm fairly sure that this is an airport
service rather than an airline service. My late in-laws needed assistance and were served very well.
There's info on Ryanair site here
but I'd also look for details on the Athens Airport site here
On the airport site paged linked above there's a link to their ebook. Use your mouse scroll wheel to flip pages (about 6 or so) to get to the English language section. (First time I've seen an ebook presented this way [and I have dozens] and I don't think it can be downloaded).