$475 is good for the mini 4K. Night Goggles has the
Wraith HD 2-16 on sale for $400, and we have the
4K max for $600. The 4K max is the better deal on the Night Goggles site, and to me the best scope in their lineup. It starts at 3x base mage, so not the best solution if shooting most coyotes in close-range, but a good performer. If shooting short-range, I would look at the 2x version of either the HD or the 4K.
The biggest need to be successful at nighttime coyote (if calling coyotes) is a thermal scanner. If a person uses a red light, digital NV, analog NV, or thermal to shoot is the secondary question. You can't shoot what you can't see. If your son is hunting 3 times a week at night, he is going to need a thermal scanner. Here is what will happen if the shooting solution is anything besides thermal. Your son will quickly complain that he can see the coyotes coming with the scanner, but he will soon say he needs thermal to shoot with. It is inevitable. I do not work in sales, but I am just letting you know,
it will happen. I realize thermal technology is expensive, but for how much your son is doing this, I would recommend taking the leap and going to thermal for the scanner and scope, right away. I would not spend a lot a money on night vision unless you go with a cheaper option because eventually it may not be used. I actually use the Sightmark Wraith's mainly for daytime coyote filming as they yield a good, recorded image. Once nighttime comes, I switch to a thermal scanner and scope. In Double Up's video, the video looks very good. He is using multiple IR source, and the coyote is coming to a bait pile at fairly close range. This is an example where digital NV works very well.