Jack keeps himself busy cleaning out the Slayer house of all the disgusting zombie leftovers that it accumulated during the few days that the Patchwork King stayed inside it, and fixing all the structural damage that resulted from the Patchwork King's use of powers inside it. This takes more than a month since there was some really serious damage to the floor in the entryway particularly, and without Chris around he doesn't have much help for the trickier parts. Still, he does a beautiful job on his own, and by the end it's all as good as new.
The Sundown Lanes and the Drawbridge remain Jack's favorite haunts. Every so often he reports back to the other Slayer fragments about what's going on in the Teffelsburg demon community. It seems that a few of Whisper's underlings tried to step into his position but soon met with a gory end, which results in the demon drug trade being mostly abandoned on a large scale (although it will always continue amongst smaller groups). The power vacuum seems to be resolving itself in the form of many smaller-time demons and vampires rising up to boss around their own separate groups, resulting in a restoration (mostly) of order after the death of the Patchwork King, but nobody dares take the position of "head cheese" for the time being. In his spare time, Jack also continues poring over the Slayer house's library in his spare time, presumably still looking for soul retrieval information, although he's pretty tight-lipped about what he finds (or doesn't find) there.
All joking about self-preservation aside, there's a definite change in Jack when it comes time to go on patrol. He rarely tries to beg out of going on patrol anymore, and seems much bolder and more self-assured in fights. Running away is now the exception rather than the rule for him, at least at first; he still tends to bolt if he gets hurt, but he'll usually stand his ground at first. His favorite weapons are the two stakes he fashioned out of the broken fish stick, but anyone who drops by his basement room will also note that he's also laid claim to the sword and shield he once made for Sabrina. You haven't seen him use it in a fight yet, however.