Victims sue other people for injury and wrongful death in accidents all the time. Apparently if you seriously injure or kill someone with your car, especially while impaired, not only are you subject to what the law throws at you, but the victim's family can also sue you, which is why you have insurance.
Suing someone convicted of murdering your loved one, for wrongful death, is no different really, except in most cases the murderer is indigent and it's not likely you'd ever be able to collect. So you wouldn't be putting out lawyer's fees for something you'll never be able to collect on even if you win your case.
TB was 32yrs old. He had many years of earning potential ahead of him. Likely in the 2-3 million dollar range (or more). His wife and daughter have lost that earning potential, not as a result of illness, which is always tragic although no one can be held accountable for that, but allegedly as a result of the actions of two individuals who are charged with his murder. It is certainly his family's prerogative to sue for wrongful death, should they be convicted, to try to recoup that lost earning potential but I have no idea if they would consider it.
MOO
When you sue someone who was responsible in a car accident, that is covered by insurance. That insurance usually carries a million dollar liability. This means the insurance will pay up to that amount. If in the remote chance a judge rules more is due that is when the driver is sued for their own assets. That is a hard road to travel, and will take a very long time, money and no guarantee of winning. MOO