I'm honestly not sure what can be done about it, really, unless the NFL and other leagues where this is a frequent problem go to the point of banning players from the sport after a minimum number of concussions. I share one commenters concern about how common such conditions are in the two other brands of rugby. concern unabated by the attempted "rebuttal" that NFL players tackle with their heads rather than their shoulder. Tackling with the helmet has been aptly called, "spearing" and a personal foul at every level for decades; at a minimum it's a 15 yard penalty, but ejection is possible and, if flagrant enough, refs can technically enforce any penalty up to and including game forfeiture. Largely as a result of more concussions further encouraging research on their long term effects, recent years have seen the introduction of unsportsmanlike penalties for "leading with the helmet" and "helmet to helmet" contact, and ANY contact with a quarterbacks head is also illegal. This article claims spearing was "dismissed" years ago, but it's still on the books in the pros and college; I admit I can't remember the last time I saw it called, so it seems like it's simply no longer enforced (why the League felt obliged to create a new duplicate rule rather than enforcing the original one I have no idea).

Though it had nothing to do with his motives, this actually makes me a little glad Jerry Jones cut Troy Aikman when he did; two concussions in a single year proved once and for all that what was once arguably the best offensive line in NFL history couldn't or wouldn't protect their quarterback anymore. Of course, most NFL players don't HAVE offensive lines whose JOB is keeping them from getting hit. Offensive linemen themselves certainly don't, and they start every play on the line of scrimmage literally and often figuratively bumping heads with defensive linemen right in front of them. Both offensive and defensive linemen routinely weigh in at 150 kilos or more, and whatever you've heard, very little of it fat. This is just one of many tragic cases of what can result. Note that though the head slap is more commonly associated with defensive linemen (most infamously its pioneer, Hall of Famer Deacon Jones), it can and has been used just as effectively by offensive linemen AGAINST defensive linemen (in the case, the most infamous exemplar is probably Erik Williams, who ironically had his best days protecting Troy Aikman when they won three Super Bowls in four years).

I dunno, maybe the article I linked is right and any intentional contact with a players head should result in a heavy penalty and fine against the player who initiates it. That might not be enough, however; in many cases the concussion is caused not by a player striking another helmet (with his own or part of his body), but by the impact of their head with the ground following the hit. That risk only rises in stadiums with particularly hard surfaces; astroturf is notorious for prematurely ruining running backs knees due to the stress produced by concrete foundations. Ultimately, there's little to no chance concussions can be eliminated in full contact sports, professional or otherwise; they can only be minimized. Penalties and fines for spearing or intentional blows to an opponents head should be embraced as an obvious and simple way to do that, but the only way I can see to eliminate concussions in football is to eliminate tackling, and probably blocking as well. Here's hoping that as the serious long term effects become more well known players will only accept that risk knowingly, and their doctors can convince repeatedly concussed players to retire before the damage becomes severe. At that point, Aisha's right; whether they choose to play or not is ultimately they're call, and that's fine as long as they make it aware of the risks.