Make him follow HAIP DIET.  Add Kapikachhu churnam to above herbs. This will help. Allopathic medications will continue as is. You cab try vaidyaratnam Ashwagandha gummies. He will enjoy them and they will help as well.

Don't self,medicate, consult your doctor.

It's manageable through ayurvedic medicine and if he includes yoga with then can be cured permanently. Allopathy have no cure for this

Hi, it’s good that your father is already on proper allopathic medicines for Parkinson’s and Alzheimer’s. Herbs like Shankhpushpi, Brahmi and even Ginkgo can help in memory and nerve functions, but in such conditions they have to be started very carefully—dose, form and timing matter a lot, especially since he’s already taking medicines like Sindopa and blood thinners. Instead of starting directly on your own, it’s better if I check his full history and current condition first. You can book a consult with me, and I’ll guide you on how Ayurvedic support can be safely added along with his ongoing treatment.”

Got ur concern n willing to help ur father. it's very tricky i.e. science and ur intention... U can try for 7hrs to 7day, But no self medication. The person grabs the destination by the skill n awareness alertness where to stop and foe that Authentic Ayurveda expert adds value n role, whos reaisting u to take professional help

Start proper ayurvedic medicine..

"In elderly patients with Parkinson’s and Alzheimer’s, starting Ayurvedic medicines along with ongoing allopathic drugs should be done only under supervision, as interactions may occur. Ayurveda can help improve memory, coordination, and nerve health, but the dosage and combination need personalization. I suggest you consult me before starting any Ayurvedic medicines."

Consult ayurveda physician for proper diagnosis and root cause of ailment before consuming any medicine

Yes , no side effects