1. For verbally abusing a person no serious criminal case is registered.
2. So on this account there is not much to get concerned.
3. Since your father is getting tortured he can visit the police station and lodge a complaint in writing.
4. If the tortures upon your father js serious then police can register FIR against him.
5. So , next time if your uncle tortures your father then instead of making hot talk with him. ask your father to lodge complaint with Police in writing.