I found the solution to the bug and wanted to share it with you, since i read all over the internet that people have a similiar bug like me.
The BUG was following: Once you return to whiterun with Vilkas, he tells you its time to attend the funeral, but you neither get the quest nor does any npc attend any funeral.
it has nothing to do with the winterhold jarls helm. that is another possible bug.
we have a different one
and i know how to get around it. i played around with various methods until i told myself **** on everything. ann i typed "killall" in the console while in whiterun.
and after that i typed "setstage c06 1" and it actually worked. i figured it had something to do with a glitched npc. and so i reloaded and went to every npc and used "kill" and setstage. and it turned out to be the greymane blacksmith at the skyforge.
SO all you got to do is go to the blackmith "kill" him, "setstage c06 1" and "resurrect" him of course. (he doesnt die actually since he is important, but he squirls around on the ground if you dont resurrect him. thats it. i hope it helped you. greetz fb