Call child protection services to make your own report. If they ignore you try looking up Children's Ombudsman. You can find yours by country and area. Then give complaint about what they're not doing and is happening with your grandson. Don't stop trying to protect a child. They do deserve to be treated as any human. Good luck.
P.S.
My rule of thumb is, 'There is always someone above someone else.' You just have to keep reaching until you find some help.