Trying to convince her this is paranoia related to dementia and he would not try to drive her out of the house. She recently moved in downstairs and she is convinced since that was her grandson's space prior that he resents her taking the area of the house and saying he is purposely causing loud startling noises in her room and stealing her things and turning down her heat. None of this is happening and we will offer to show her proof even but to no avail. Tearing me up that she is not happy here now and that my son is targeted. Not feasable to block all noise with pets as well running around! Looked into sound proofing floor and ceiling in her bedroom at least, but trying to pay and install - just one more thing on the list of what I need to do and already maxed out. Someone suggested ear plugs but I doubt she will do that.
Trying to convince a person with dementia that something is not so, or is different from what they believe, is impossible. To try to understand this disease, I’d suggest you and your son navigate around this site and do some reading of what’s posted here on this forum and on the other pages written by the experts.
To be honest, when my mother began acting out the way your mother is, I began researching facilities. She lived in an apartment on her own and began calling 9-1-1 and the police regularly because she was convinced some man was stalking her.
You will not convince her that your son is innocent of all these accusations. She is focused on and obsessed with him. Until she find another obsession, unfortunately, he’s it. You can remodel your entire home to shut out pet noises, music, television and even everyday conversations, but it wont help.
Its up to you to decide how much more you will take. You will eventually exhaust yourself trying to accommodate her.
Talk to her doctor about meds to deal with this change in her mental status.