And he keeps getting himself 'killed' into essential mode. And he will only converse with me when in protected mode. So right now he is at fort Dawnguard and the second he gets up he begins attacking me and is immediately attacked by Isran and Serana. Waiting 24 hours didn't help.

So far tcai and setting his aggression to 0 doesn't do anything. I also tried adding him to the player ally faction. These are the commands I tried:

'tcai' furing comat

select Dexion then 'setav aggression 0'

then 'tcai' again

I also tried selecting him and adding 'addtofaction 0005A1A4 0' and the same but with rank '1'.

A big part of the problem is he immediately begins combat as I enter fort Dawnguard.

I really need your help guys, thanks!

TRY THOSE OUT:

1. Open the console and select Dexion, either by clicking on him or entering prid xx007b88 (the first two digits vary depending on loaded mods), then use the command setav aggression 0. This makes Dexion passive again and the quest can proceed normally.

2. With the Dragonborn DLC, it is possible to use a two or three syllable Bend Will shout on him to prevent him from being hostile. If Dexion is injured on the floor, simply use a healing spell on him to continue with dialogue.

Repeat these steps if he remains busy, as he will eventually continue the quest.

3. If you are an Imperial or have a high enough Illusion skill, you can use Voice of the Emperor or a spell to calm him and continue with the dialogue.

You will have to do this every time you walk into Fort Dawnguard though, so if you are using Voice of the Emperor, wait a day for the power to reset.

Good advice Mark!

What finally worked:

before entering the cell where Dexion was in combat typing 'tcai' in the console.

then, clicking on Dexion and clicking reset 'ai' and disable/enable, then leaving the cell, waiting a few hours (after re-enabling tcai)

so he is not in combat and was able to read the scroll to continue the quest.

Only problem is afterwards he wouldn't converse with me, not even his general dialogue about elder scrolls. Just stared at me blankly after selecting the dialogue. Hopefully once I beat the quest objectives his new dialogue will enabled.

That was pretty stupid of beth to make an essential character automatically aggressive to the PC as part of a useless quest element, especially knowing how bad the ai can break at times....