loose bearing race - K/H disc hub

You forgot to mention,
Your sons profit when he does the repair $100.00
Your sons profit when Loctite is used $0.00

Now have your son provide a functional engineering reason why Loctite 660 when used properly would not be an appropriate repair.
That means that he would need to look at and read and understand the physical property’s and repair specifications of the product. Those are generally listed in post # 25 that same post also has a link to the complete product specifications,mentioning that just to make it easy for your son.