those setups aren’t really good. Much better is to play 2cp, put one ana on your team and 2-4 ana’s on enemy team. Crank up their health to like 300-500% (if you have too many ana’s they tend to stack and you get a lot of lucky shots, which you don’t want in practice). When your ana contests the point, they will contest it indefinitely. The biggest perk is that when they contest they run around really randomly, which makes it much better practice than the ana’s in that clip. They seem to just run in straight lines for the most part.
Best map in my experience for this is hanamura second point (if you have difficulties to get through the first point, just dps every ana to one hp, and then finish them).
The reason someone is very good at aiming, is usually cause they invested a lot of time into it. Me personally i started CS at 5 or 6, im 20 now and have played every iteration of CS. Been the highest rank in nearly all FPS i have played, if it had a rank. My advice is CSGO and their custom training maps, learn a game like csgo and better yourself, if you don´t want to be unuversially better and only better in Overwatch there are some aim practice games out there. You would have to set them up tho.
Aiming transers to all aim heroes.
For sym the aim requerment isn’t as high as on Widowmaker/Ashe.
Even so they are a difrent type of aim, with sym you want tracking and playing stuff like Tracer, Zarya can get you that. My advice wil be to just play your heroes in QP tracer, zarya, sym or moira have kinda the same aiming requited but Zaryas/ Tracer are the harder once, focus on settings and getting used to the settings/ developing muscle memory and reading animation etc. Even so playing alot of widow, mccree, ashe is by far more aim demanding so people end up focusing on that.
Aiming transfers across heroes, but there is a huge varience in what kind of aiming it is. Is it tracking with huge arm movements. Is it flicks with wrist. Is it predictional aiming with projectiles or is it precise aiming with hitscan. So first he needs to tell, what kind of heroes he wants to play, to determine the best way to practise, outside of playing the heroes.