The only way you can get a catfish to be social when its typical behavior is the opposite is to remove the hiding places for it. Or keep the lighting in the tank to either very low lighting or no lighting. This works for pl*cos that like to hide. Place the tank in a room that you are in on a regular basis.
Other than that i would just wait. thats what i would do. For me thats the draw of catfish. They dont always come begging for food. sometimes you search for them. thats part of the fun. Finding that fish that you forgot you had.