Pay Dirt Photo illustration by Slate. Photo by Liubomyr Vorona/Getty Images Plus. Pay Dirt is Slate’s money advice column. Have a question? Send it to Kristin and Ilyce here . (It’s anonymous!) Dear Pay Dirt, My youngest sister, who I’m pretty close with, has had a lot of financial troubles the last five or so years, including huge unexpected house repairs (HVAC, mold, flooding, etc.), medical bills from accidents, dental emergencies, and more. Her marital situation is not financially stable, but she is self-employed in a very essential field (where self-employment is the standard), though there have been issues there with paying self-employment taxes. She is essentially a single mom (her marriage is not to her kids’ dad) and she is often troubled that she can’t always provide for things for her kids (electronics, cars, presents, parties). She used to go to my dad for financial help (he has since passed away), and now she often comes to me.…