Yes, he can change the starter motor and no, he does not have to buy a brand new one, he can also get the equivalent on eBay from a parter. The motors from the CBR600 usually fit.
They are Mitsuba SM-14, you need to make sure that the motor bracket is the right one (the two holes come "flush" with the knob in the back, not with the body of the motor, if you look you will understand).
You can get a used but in great shape starter motor for about $10 to $20 if you know what to look for.
Yes, he does have to change the bracket. The bracket costs around $45 and Dan @ Motoxotica usually has one in his inventory.
No, it will not be enough to start the bike cold on the button. It's an 03. It may help sometimes, after all I can start my 2001 501 cold on the button sometimes, usually in the summer, and when the engine ran less than 24 hours ago, but that's not a given.
Powercell, I am ok with you ignoring my posts, not a biggie.
Have a great day.