Is Prisma open source?

Yes :) https://github.com/prisma/prisma

Yup, there's no worry of lock in.

Highly controversial statement: you can still get Kratom legally online and in some states. There is an opiode like effect. It's worth looking into if your grandfather is suffering.

*edit: didn't see the comment right below this one! Thats +2 for Kratom!