My question involves criminal law for the state of: California

Hello, any/all help for my situation would be greatly appreciated!

Back story:
My mom and dad divorced in 2000 after 20 years of marriage. Because my dad threatened to challenge my mom for joint custody (and we didn't want that), my mother let him claim the family business in the divorce as a trade-off for sole custody. There was a $7,000 tax return that the court ordered they split equally, but my dad apparently forged my mom's signature and kept the entirety of the $7K for himself. The alimony and child support dissomaster was set at $2K a month - $1 K for each. I turned 18 in 2001, and the payments were reduced to $1K a month, for alimony only.

During the last few years of their marriage together, my mom started an affirmative action-based small business, of which she was the CEO. During the 5 years the business was operational, my dad forged my mom's signature on various IRS documents, and effectively "stole" her social security; deferring the payments to his name (as they were married at the time). My mom believes that when it comes time for her to collect social security in the next few years, she will receive nothing from the years she operated her business with my dad -- as he gets the credit for it.

What we want to know is this: since it's been so many years since this happened (it was a CA women's business in the 90s), (a) is there a statute of limitations on reporting my dad's various forgeries and the fraudulent taking of my mom's social security? and (b) what would that S.O.L. be?

Also, is there *any* chance she could get her half of the $7K back from that tax return of 2000, or has it been too long?

My mom waited all these years to take action against my dad because he paid my college tuition, and she knew if she spoke up he'd leave me hanging... So she didn't rock the boat. Now that I've graduated she wants to take action.