Can he read at all? Even basic reading? Did the Doctor that did the recent diagnoses recommend any follow up to help your husband learn to read?

I would suggest getting both paper and audio books from the library and he can listen as he reads along.

That may help him gain greater skills. And the more he reads the better he will get. Eventually his brain will develop a kinda auto correct when he reads. It's hard to put into words... as I read, when my eyes and brain are not communicating correctly the most logical word (in context to the subject being read) is inserted.  It is just an automatic thing that happens.

Start with something simple but of an interesting subject matter to him.

I do wish him the very best.