This is a S&F mission that become available as soon as you finish the main storyline. When you meet Trevor's mother in his safe house, she ask you to find "Deludamol". All you have to do is to find a "Deludamol" van and bring it to Trevor's safe house to complete this mission. Just search in hospital parking and you'll eventually find one. It's a grey (or white) van with the word "Deludamol" written on the side.
For your second question... did you try to hold up a store already ?? Or is it a bug that doesn't mark it as complete?
If you don't already try it... just go to any store (each one are showned on the map) and put your gun under the nose of the clerk. Wait until he drop a bag full of money on the ground, take it and escape the cops.
Should do it.
Last edited by NoNameX03; 01-24-2014 at 12:04 AM.