I will try to explain this the best I can, my friends truck is used at his cabin maybe 10 times a year, 3 weeks ago he drove it, parked it and went back out to start it 2 hours later and it would not do anything, absolute dead everything, the battery is good. It will turn over but not fire when he touches both terminals on the starter relay, he ran a wire from the positive on the alternator to the positive on the battery and it started, all accessories except the headlights worked at this point, unhooked the temporary wire from the alternator to battery and it kept running, shut the truck off and tried to restart it and totally dead again. One other bit of information is that the steering column was replaced because it was floppy many years ago and the replacement column is floppy also. Any ideas what to do next ?

You have an open somewhere between the starter relay large terminal "batt" terminal to/thru fusible link/to/thru bulkhead/to/thru ammeter to the "welded splice" where power normally T's off to the headlight switch/fuse box/ign sw. You jumping the batt to alt fed juice in reverse in/thru the bulkhead to the "welded splice" & fed everything that way. Start with the fusible link (see if it has continuity) & seperate the bulkhead halves for that main "in" circuit & check condition of the 2 brass terminals for the "in" circuit from the FL & if good check the ammeter. EDIT it continued to run when you removed the jumper cuz the alt was powering everything like normal (ex for charging the batt) cuz there is an open between the batt and the "welded splice" so that batt cannot be charged nor can the battery power the system to run it or crank it (unless you jump the starter relay like you did which bypasses the open from starter relay to somewhere downstream toward the welded splice). With no jumper it will not start because of that open and the alt is no longer producing current

Seems like a burned fusible link. With that, you can still bypass the break and start it from underhood.

If the positive terminal on battery cable has two heavy cables coming out of it, make sure there's no corrosion under the lead itself of both.

My bet is a fusible link. I have an 88 and was surpised to find there are a number of them on this one. Chased a similar problem last summer for better than an hour before I finally realized there were more than one.