My grandmother is suffering from delusions, how do I convince her to see a doctor?
One of the things you have probably learned by now is that you can’t really reason with your grandma at this point. She is not capable of rational, logical argument. If she has dementia this is probably because the part of her brain that is involved in higher, abstract, rational thinking is no longer working right. Arguing in this situation or trying to reason with the person often makes them angry. Their reality is not the same as yours.
When your grandma brings up the affair, family members need to try to reassure her or distract her, not argue her out of it (which doesn’t work). You want to respond to her emotion, not her words. Is she feeling scared? Insecure? Angry? I might say something like, “I can see that you are really angry right now.” I’d give her a chance to respond and then try to distract her in some way.
Getting her to the doctor is really important, but not easy. You may have to resort to less than the truth in order to accomplish this. I know that does not feel comfortable, but you have to remember that you are doing it for her own good and she does not have the capacity right now to understand that. There may be any number of medical things going on that are contributing to this escalation in behavior. In similar circumstances, I have taken a person for ice cream or some treat on the way to the doctor’s office without stating that that is our destination. I’ve also called the doctor’s office, explained the situation and tried to arrange to be seen immediately. It helps to fill them in ahead of time with a letter or fax that describes what is happening.