It's probably just a phase, but by letting him watch videos and spend time with Mommy and Daddy, and even sleep on the couch with Daddy, you are just reinforcing the behavior that you want to stop. Maybe he was scared for a couple of nights, but now he knows that if he doesn't go to bed he gets to watch movies with mom and dad for 4 hours. What 2.5 year old wouldn't like that? My little guy would LOVE it!
It will not be easy, but you just can't give in...if you really the behavior to end. 2.5 yrs old is about the time fears (like dark, monsters, etc) begin. You have to put him in bed and talk to him in there about it. Look around the room and make sure "everything is safe". Give him a flashlight to sleep with, if necessary. Make sure he is cozy in bed, favorite blankets, toys, etc. Do you still use a monitor? Set it up and make sure he knows what it is for - so you can hear him if he needs you. Be consistent, but keep him in his bed. Is he still in a crib? If not..and he gets out of bed on his own...keep putting him back in bed. Maybe even sit with him for a night or two until he falls asleep. Sit on the bed, then move to the floor, then move to the doorway, then the hallway, it may have to be gradual like that. Do what you need to do to help him feel safe, but don't give him extra time up or sleep with him or watch movies together if you don't want that to be the way he learns how to ALWAYS go to sleep.
Good luck and be strong. It is tough to change learned behaviors and habits, but it is worth it in the long run. Give it a week of consistency (bed at normal time, stay in bed and sleep) and he will most likely be back to his normal sleeping routine.
PS I noticed that someone said eliminate naptime so he is sleepier at night. He may be ready for this at 2.5 yrs but probably not. If you try it, you'll have to put him down even earlier at night time. Kids that age need at least 12 hours of sleep total - per day. When they are sleeping, their brains are developing....so you don't want to skimp on that. Not to mention the crankiness. :o)