Take your steer off feed COMPLETELY for about 2 days. Give him some "gut bugs" either by probios, fastrack or other product. Then start feeding GRASS hay. If that doesn't work, the rumen is probably completely dead and all the "cures" will not solve the problem, they will just reduce the bloat.
If you are close to a vet school take the steer there and have them use their fistulated animal and get rumen juice from that animal to put into your animal. OR if you are close to a locker hold your steer off feed for 1-2 days, be RIGHT THERE when they slaughter a bovine, IMMEDIATELY cut into rumen and get the contents, then within a 10-15 minutes get that into your animal via stomach tube.
You can stop the bloat by using therabloat, soap, baking soda etc, but it will continue to bloat until you get the rumen functioning.