First time i see this really.
When i get in NPC's house and spend some time there, he attacks me.
And when I enter his place, he stops his current package and watching me around the room.
The door is red but unlocked, and I understand that I m tresspassing.

I tried to five ownership of the door to the player.
I tried to put the NPC to PlayerFaction.

I dont know what to do to fix this.
Any ideas?

set the ownership of the cell to none or the player. Hes attacking you BECAUSE you are tresspassing.

Yes thank you!
I just set his place as public area and now i shall find a way to make him lock the door when he goes to tavern.
I believe through the package...