This is how they could probably achieve "immortality" in combination with "cloning".

I am still in the beginning of digging.

But i am pretty sure i am on the right track!

"When we die, the neural connections that make memories start to degrade. But what if our brains could be preserved? What if our memories could be backed up like computer data? One start-up company says it’s possible."

https://www.brainpreservation.org/asc_rabbit_fulleval/

https://www.medicalnewstoday.com/articles/321235