Dementia has a cause, not visible, nor treatable in this dimension.
Dementia is a damaged soul. To heal it requires a balance of Understanding and Forgiveness,
on your part.
A soul can be damaged by ignorance and misunderstanding. In Dementia, you walk in darkness, when you understand the power of your being, the power of who you are and why you were made, then you can forgive, you're free, the soul is healed.
We were created out of Love to live in Love. All else is misunderstanding.