The report doesn’t mention how old great-grandpa is. My dad is 90 years old. He doesn’t see or hear very well and there are times when he has trouble concentrating. I would never entrust my grandchildren into his care under any circumstances. It wouldn’t surprise me to find out that this old guy had similar limitations. Maybe the family needs to re-think their options.
Given some of the families I've seen lately, great-grandpa could be as young as 55-60.