Originally Posted by .:Lord Revan:.
Griff if that is missions brother after he runs out of the tuscen raider camp i think he is in the tatooine job office building.
Afterwards, you take have the option to undertake a quest for him - find a tach gland and give it to him. After that, he runs off once more and you'll never see him again.
It's kind of an incomplete quest TBH.