If you are thinking of having a cataract operation, be warned - they are not always as successful as we are led to believe.  Before his operations, my father was still able to read the newspaper with his normal glasses, albeit with difficulty.  He can now only read large print books using a magnifying glass.  One eye is so bad he can't even guess at the top line of the opticians chart.  After repeated visits to the hospital, he has been told nothing can be done.  Although most operations seem to be very successful, think carefully as things can go wrong.

I am very sorry for your father. I know this will not change very much, but it can make _some_ difference: try getting him a magnifying glass with a built-in light. Sounds gimmicky but it does enhance the image.

There are hand-held models as well as more serious ones with a thick lens that can be stood on the book.

All the best, Leszek.