Personally, You should've gained the ability to summon him to help you defeat Miraak.

I think he was still a part if the dragon cult, meaning he's definitely not a good guy. His enemy just happened to be your enemy as well. The book claims that Vahlok defeated Miraak, but I took that as Vahlok lead the forces that attacked Miraak. Vahlok may get credit for the defeat, but does it really seem likely that he would be able to defeat a guy who ate dragons for protein?

Unrelated theory: Miraak's dragon cult could've been founded by followers of the dragon priests who were deduced by Mora.

Vahlok = 1 bone meal + (250) gold.

....that's all there is.

no weapon, no mask, no pendant, no ring, no books, no new spell - nothing.

word wall behind the casket.

Once inside the Tomb - good luck trying to get out of the tomb (Xbox)

Xbox will freeze upon trying to leave the Tomb perma. Turning off auto save did not work either.

That is a problem with your game having trouble running, not with any bug with getting out of the place. If you are getting unending loading screens, areas that do not load properly, and more than usual crashes on loading screens, you will have to follow the official solution to the problem and clean the system cache and uninstall all the DLC, the patch and the game if you have it installed. With a fresh install it will run well enough to get you through Dragonborn. There is still at least one spot in the game that causes the Xbox 360 to crash occasionally, but approaching it a bit slower will most likely solve that.

Link to detailed solution by any chance mate?

http://www.gamesas.com/topic/1426775-starting-dragonborn/page__view__findpost__p__21895466

They should sticky that solution with a better thread title considering all the trouble adding Dragonborn is causing some of us. I ended up having to do it and it worked for me, I have two characters with a lot of play time, Dragonborn was unplayable for one and just annoying for the other, my lower level character had no trouble with freezing. I had the autosave problem since the 1.6 patch and had to turn of autosaving, so two of my characters are really trying out those performance improvements we get with each patch.

Cheers mate!