When he was sniper or whatever, the enemies were glowing red.. is that a perk or follower perk?

laser weapon crits??? make enemy glow to red and turns it in to ashes,

Yeah. When you have Boone as your companion, enemies will be highlighted in red when you're using your scope or aiming down the iron sights.

the enemies turning red is a follower perk you get it when ever you have boone follow you. he is in novac in the dinosaur at night

thanks guys

That's a follower perk from Boone, and is only active while he is your campanion.

Edit haha guess they beat me to it