This a good forum to learn from, so welcome.
My son currently is paranoid sz. He is steadfast in his no meds of any kind. Even OTC pain relievers. We are going along with his stance, but have said no meds also mean no street drugs as they are meds too–and that includes cannabis–and have side effects also. We have also said if he becomes a danger to himself or others he will be involuntarily admitted and back on meds. There need to be healthy boundaries set for any relationships and that includes relationships with our MI loved ones. So consider what you feel is in his best interest, communicate it, and follow through.
Back to ‘normal’ is not our goal. Would he be better on meds? Probably. But he is functioning in his odd sort of way and we have a relationship which is mostly good.
As much as you are drawn to the idea of sneaking in drugs, please consider what may happen if you do. Maybe you will see some improvement, but down the road, chances are good he will go off meds again and remember what you did this time.
This will be a bumpy ride. Everyone’s course is different and in the end only you can decide what is best for your family. Best wishes.