Inherited traffic violations, unserved lawsuit, grand jury testimony

The following three questions, submitted to FOX 26 senior legal analyst Chris Tritico, were answered during a FOX 26 Morning News segment on Sept. 29, 2015:

We had an extra car we sold on craigslist in 2012, we weren't exactly sure how to go about the 'selling process' so we made a written out agreement that we simply signed and had the new owner sign as well. We only got a copy of their out of the country ID and gave them the entire title. A few months later we received tickets in the mail for the new owner running red lights and going through toll roads. We contacted the new owner and they stated they sold the car to someone else and don't know where they put the title, they're refusing to pay any of the tickets. Is there anything we can do about this legally?

I filed a civil lawsuit, pro-se, against a company where I once worked. I paid for the constables office to serve the defendants. However, when I check Harris County Clerk's website. It says they attempted to serve the defendants but they failed. It reads "Unserved" in the data-base. I think the company has moved. What do I do now?

My wife was a primary care provider for a patient whom accused an MD of inappropriate touching. She was the primary nurse. She was called to a grand jury. Should she have a lawyer as a witness?