The damage could be quite extensive since this has probably damaged the power supply and every part of the radio is connected to the power supply.

It will take some electronics skills to even assess what the damage is. You or someone will have to open it up, assess what has been damaged (much will be visually obvious but not everything must be) and decide how to proceed.

Honestly, buying a new one is probably cheaper than repairing one damaged this way. Labor alone to assess the damage could cost several times the replacement cost. Only DIY might be cheaper but then if the damage is extensive not even then.