Thank you for your question. I look forward to working with you to provide you the information you are seeking for educational purposes only.
If he was a small business restaurant with less than 15 employees, then any comments about age/race/sex/disability/national origin are not legally actionable, because in order for discrimination
laws to apply to an employer they must employ 15+ employees. If he did have 15+ employees, then you need to first file a complaint to the Fair Housing and Employment Division about the allegedly discriminatory conduct towards you and they must investigate to give you a right to sue letter to proceed to court.
If he was improperly paying you contrary to the wage laws and was not paying overtime as required or giving you proper meal breaks, then this is a claim you can file with the EDD
wage and hour division as they investigate those claims and will pursue him for not paying wages and you would claim not just wages due, but you are entitled to liquidated damages in the amount equal to the wages not properly paid.
As far as you doing jobs "not in your job description" I am afraid you are an at will
employee and the employer can make you do whatever jobs they needed you to do. For at will employees there really is no "job description" by any laws so there is no cause of action there.
If the employer is violating health and safety
codes, you can also report that to the local health department, but that is not any reason for you to sue them over.