The ICR is a god weapon? It can be fun to use for sure, but it's the weakest assault rifle in Call of Duty history lol
And why recommend thermal? That's not going to help him work on practising key FPS skills; that's just going to make him overly reliant on a glow in the dark scope and hurt his progression more than anything.
Always move. Use Stock on all weapons. ARs can be used like subs (use M8A7 reflex, stock, fast mags). When you prestige, always permanent unlock the highest level items first. If you have last pick in arena, don't protect something..ban it.
Stick to the outside of the map and dont feel the need to rush or run all the time. Move from cover to cover and keep an eye out for any movement. Using the sixth sense perk will show you which direction any nearby enemies are on your minimap (this helps when moving from cover to cover to detect enemies hiding around a corner or in a room) Flick your eyes to your minimap every now and then to check where your team is spawning. Your enemy will be spawning on the other side of the map so head towards that side. You can use tacticals to stun a room that you know has enemy inside or use a smoke as a diversion throwing into one entrance and quickly running to another entrance to catch the enemy by surprise. Dont use scorestreaks like hcxd because you will 9 times out of ten be killed while using it and not often get more then one kill. I would recommend uav care package and counter uav untill you get better. Hope I helped in some way