I do not have any personal experience with an AEV Hemi swapped TJ, however I owned a 5.7L Hemi TJ that was converted by Jeep Speed Shop. There was a plug under the dash labelled "cruise control module", mine didn't have the module plugged in, but I was told by Todd at JSS that it could be purchased from Hotwire Auto and that the system would be functional. Maybe AEV used a similar module and it has malfunctioned? I'm not sure. I guess this is the downside to owning a niche vehicle, but I wish you and your friend luck in finding a solution.
Reaching out to HW is worth a shot until AEV gets back on line. Here's HW's POC: