Yeah, Toshi and a good chunk of the people in the Complex are upstairs from where Lucas is at. They would have to get through where Tom is holding Lucas telekinetically to get to Jack though, so even if it weren't already highly implausible for Toshi to know that Jack is down drinking from Nessa's body in the garage, he'd have to get around the whole Lucas situation first.
Plus honestly, the most sensible options are either to investigate upstairs where Shuya and Isa's bodies are, especially since there was the sounds of people crashing through walls, or help with Lucas since, even though Tom has him contained, I wouldn't be shocked if he could use the plants that are rapidly growing to attack in some way even while Tom's holding him immobile.