Thank you for your valuable feedback. I am very sorry to read about your father's situation. I wish him the best.

I empthsize with your feelings as my father died from an autoimmune disease (deadly ALS). Therefore I am very cautious about autoimmune dieases affecting our physical and mental health.

Yes, weather affects arthiritis. Humidity is mentioned a lot in the literature pointing out that humidity could cause the blood to thicken resulting in increased pressure on blood vessels.

In terms of temperature, there is not much empirical evidence but there are subjective findings on extreme weather conditions either hot or cold as mentioned in this resource https://tinyurl.com/ywxvd5ue