Magnets, how do they work? LOLZ
"The magnets, he says, would put a brake on the impact before it happens."
The added weight of a magnet large enough to repel another magnet when slammed into each other would make them dangerous when striking any other part of the body...
"They are the most powerful commercially available magnets and weigh about one-third of a pound each (football helmets weigh from 3.5 to 5.5 pounds)."
So in other words, three magnets weigh less than the difference in weight between helmet manufacturers.
and the cost associated with all that rare-earth magnet material would make them prohibitively expensive (and probably run the world out of rare earth magnets, if you think about how many they'd need)
"Colello speculates that adding magnets to a helmet would raise the price by $50 to $100. (Professional helmets today can cost several hundred dollars.)"
Or, the opposite of prohibitive, in simple terms.
Also, wearing a high powered magnet on your head, all day, every day would have zero affect on your health.
"Another safety concern is whether the magnets are dangerous to have near human heads. Colello says that a 30 minute- to one-hour MRI procedure produces magnetic fields 10 to 30 times as strong as those in helmet magnets."
Literally all of your statements were refuted.