Bug: Tom, The Wannabe Adventurer

Hi, my friend and i made the quest with tom. we found the corpse, loot the letter and read it. now after some hours when we came back to the city we werent able to finish the quest. we looked in our questlog and the quest is still in its initial state also the letter is no longer in our inventory.
is there a way to solve this problem? maybe a cheat for the letter and read it egain.

to load an older save is not an option. we will lose hours of playtime and cause he moved away and we have time difference of 8 hours we only can play on weekends...