Leo came to Scotland excited to meet new friends and settle into a calm routine far from the chaos that tainted his home life before. When the young teen left he was traumatised and blaming himself for his mother's death. His father William, who was separated from Leo's mother, has told BBC News how his autistic son ended up living alone with his dying mum in a squalid house in Perthshire, littered with empty booze bottles. This was despite child protection officers carrying out a home safety check five months before. He says the system failed Leo, and lessons must be learnt. Perth and Kinross Council has upheld two complaints - in relation to poor communication and a failure to contact police for a welfare check - but has rejected other criticisms. All the names in this story have been changed to protect the identities of those involved. When Leo's mother Lauren relocated to Perthshire in January 2022 for a fresh start after struggling with alcohol addiction, William supported the move.…