Tough Day - Security Deposit Debacle

So, today I had some frustrating news. My sister and parents own a house in a historic town (aka - houses are OLD) and wanted to renovate. They felt that it would be cheaper to just move out and empty the house in order to do major repairs, so they looked into renting an apartment. It seemed too good to be true when our neighbors (attorneys who live in another state) offered us their house to rent. The house seemed perfect for our purposes, (although kind of grotty), so we ended up living there for about a year and a half. Well, our house is looking pretty good, and we moved back in mid-June, but still hadn't received our security deposit in the mail.

My sister emailed the landlord, who stalled for a while, and now she is saying that the house was "too dirty and grimy" to rent again, and she would have to keep the 2,000 deposit to have the house cleaned and to make repairs. I know for a fact that the rental house was much cleaner when we left than when we moved in! In fact, I thought at the time that my family really went overboard to make the house rental-ready, (repairing stuff, repainted chipped walls, and cleaning very thoroughly). So I'm not sure whether the owner is just relying on her real estate agent, who may be blaming us for the slow rental market, or whether the owner is crazy or just trying to take advantage of my family. Or maybe she just didn't realize the condition of the house when we moved in? Either way, this situation is so frustrating to me.

I looked up the law about security deposits in my state, and I'm pretty sure that even if the house was dirty (which it wasn't) she would not be allowed to deduct cleaning expenses from the security deposit. Also, by waiting longer than 30 days to give the deposit back and by failing to provide us with an itemized list of damages, I know that in small claims court she would owe us double the deposit. However, my too-sweet-to-deal family won't even consider asking a lawyer what to do, let alone harbor the idea of taking their neighbor to small claims court. What should I do in this situation? Is it better to make nice with a cheating neighbor than get the court involved? Before I went to law school I would have thought that anything involving an attorney would be extreme, but now I just see this as a fair way to settle a dispute. As a Christian, is it wrong to take someone to court like this, even if you're in the right?