I'm supposed to go in and deliver the evidence about the captured son but their house is locked and if I pick the lock they call the guards. Is there a console command I can use to make this work or am I supposed to come at a certain time (I've tried at noon and midnight and the door is always locked)

Use the back door.

both doors are locked

Okay, you have mod(s) that screw your game then, because the back door is never locked in the original game.

Just go in at day?

in the meantime try this:

prid 1A686moveto player

These two commands launched one after another in that order will bring Avulstein to you. (Do this behind the house, so that nobody "sees" him. )

Edit: before that, try entering the house by clicking on the doar and using the command:

unlock

Try and deliver the letter to Avulstein even if himself or anyone in the house keep saying "you need to leave" or "can ... have a bit of privacy", etc.

rats. Weird that a mod would have that effect.

Locked in the day too.

Yeah, sometimes the day-night cycle seems to get messed up for certain characters. I had a similar thing happen after I cleared out Kolskeggr Mine and had to use the console to talk to the people I needed to.