Proof of no soul/afterlife/god, or something else?

A person has a stroke, a brain injury etc…, loses some brain tissue which leads to memory loss. The person doesn’t remember a lot of their experiences and/or people from their life. If someone had a soul wouldn’t it retain the memories/experiences? If the memories/experiences are stored in the brain that can be damaged or die, then when we die is our soul is void of memory or experiences or what do you believe?