Please issue a final notice to him. If he repeats the same in the future, you may terminate him without any prior notice. Two points must be taken care of as mentioned below:
1. When giving the final notice, enclose copies of all previous notices issued and accepted by him.
2. Also, include a sentence stating, "If these kinds of activities happen again, the company may terminate you without further notice or prior information."
In my opinion, labor courts and labor offices always favor employees. Therefore, before terminating him, ensure that this final notice is issued. Having issued the final notice, you will have written evidence that can help you if any litigation arises in the future.
Regards