Gosh, how terribly hard, I'm so very sorry you are in such a difficult situation. Many of the drugs we take do cause memory issues, but what you describe sounds extreme and must be very frightening for both you and your wife. Does your wife know when you are at your parents house to sleep, and has she started to do other strange things and not recall such as getting up to go out in the middle of the night, cooking a meal and forgetting to turn the the oven on (or off).
I'm not sure what you mean by catheter? To me a catheter is what is put in for aiding with urination so the patient doesn't need to get up to toilet. I'm sorry for my ignorance.
Do you have a pain and or medication diary? It can help you to record what time medications are taken and what type of behaviours occur as a result of the meds and what changes in her behaviour as they wear off etc. Is it possible if she is forgetting things she is doubling up on her medication intake? You could try post it notes to record things you discuss and get your wife to write it also so you can show her you have had that discussion and that you are talking and you are not angry. That said, it would not be easy, as she could well take offence initially until she can see for herself it's happening and then, she may well become upset as she realises that something is very wrong.
I don't know what LNI is either, I come from a different country so again excuse my ignorance. If it's about to run out, can you make the most of it before it does and get her into a hospital where she can be monitored round the clock for 48 hours or so?
I really do understand you are in a difficult place, just know, you are not alone, our partners face situations as well from time to time and it's only by having open and frank conversations between us and with our medical practitioners that we can sometimes all move forward together at the same pace.