Timothy was with Philip since he was a child. Timothy was a playful dog. Philip considered Timothy to be a special dog. Philip thought Timothy could always protect him.
1:
Timothy was with Philip since he was a child and was considered to be special by him who was a playful dog and could always protect him.
2:
Timothy was with Philip who considered him to be a special dog and could always protect him as he was with him since he was a child and was a playful dog.
3:
Timothy was a playful dog who was with Philip since he was a child and was considered a special dog who could always protect him.
4:
Timothy was with Philip who was a playful child and considered him to be a special dog and could always protect him.