Moy, from East Kilbride, told Scotland News: “I really believe Kayden’s death could have been prevented.
“There have been so many chances where this could have been stopped and it wasn’t.
“They have been allowed to repeatedly re-offend and it has cost my son his life.”
A council spokesperson said: “This has been a tragic event, and our profound sympathies continue to go out to Kayden’s loved ones.”
Cole Turley, 18, and Jay Stewart, 19, were sentenced to life imprisonment and ordered to serve a minimum of 16 years for Kayden’s murder.
A third boy – who was 15 at the time and cannot be identified for legal reasons – was detained for at least 14 years.
Two of the boys were known to social services and Moy, 38, said South Lanarkshire Council had “serious questions to answer”.