Legal Question in Landlord & Tenant Law in California

If he is a month-to-month tenant (and assuming you are not in some sort of rent control district) you can give him either a 30 of 60 day notice to termiante the temancy (30 days if he has resided in the premises for 1 year or less or 60 if he has lived there more than 1 year). Month-to-month tenancies can be terminated for any reason not prohibited by law (i.e., based on race, religion, national origin, etc.). If there is a written month-to-month rental agreement he may also be violating a provision in that agreement which might allow you to give 3-days notice to cure. If he refuses to vacate at the end of the notice period you need to file an unlawful detainer action to evict him.

Yes. You can evict a tenant who is creating a nuisance after serving them with a notice. These cases with mental issues are tricky because you get into reasonable accomodation issues. Please call me to discuss this matter. My office handles unlawful detainer eviction proceedings.

Both answers above are correct. But evictions can become tricky and with a tenant with mental problems such as you describe, in the long run it will likely cost you less money, ans certainly less pain, to hire an attorney to handle the matter.