as i have it, his sister died in a mining accident with their mother. but what if she didn't die and everyone was declared dead because they didn't want to do the clean up right away to look for survivors? after the dust settles so to speak, they do the clean up, find survivors and she's been serving thedes-korso for whatever they needed her for (think qi'ra from solo) but she's been wanting out of it since the beginning and to find thomas. that's the beginning of it. if you're still interested, i'd be happy to discuss more!