Yes! There are written materials available. Doctors often have pamphlets and brochures to explain most types of common surgeries. You may want to take the time to get some of these materials from the doctor's office. Sit down with your mother-in-law to review them together.
Some patients don't like their family to interfere. You may need to express interest in the operation by reading the materials yourself. Perhaps reading important parts of the information out loud will help.
There are even some videos out now but they may not have closed-caption yet. Adapted materials may become part of future patient instruction as more and more older adults with hearing and vision problems have surgery.