I need help ASAP! I've tried 20 different ways and countless hours trying to get past this quest. After I get done talking to Preston with the rest of the minute man and I tell him one of the 4 options he gives me of my tactic to take the castle everyone readies in position except for him. He just stays in the same spot while the rest of the minute man get in position. I even go ahead and kill all of the monsters and eggs and he is still hanging out at the same place. Has anyone heard or have this problem? Please let me know how to fix it!

There is a fix for Preston's disappearance, but not for this one.

Try to load a previous save.

I did that, I think it's because I used him before the quest and he has all of my gear that I gave him maybe?

Well, load a previous save and make it differently this time.

...and SAVE AS OFTEN AS YOU CAN. !!!

What do you mean by make it differently? As get a different companion and make it to the castle?

No, i mean don't give him your gear this time, in case something goes wrong again with that quest.