Always, ALWAYS check your receipts before leaving, I insist on snapping a photo of the completed ticket with tip and total tabulated, and also make it an even number every time, or something unique going forward - like every single total must end in ".07" so the tip might be odd, but I can go to my bank for a dispute and say "as of XX date, I started adding the tip so the final total always equals ¢.07. This disputed charge does not, and I can show you the image of the restaurant copy I left with the waitstaff. It gives you more ability to show that the restaurant is in the wrong if you establish some sort of proof.
Similar happened to my husband, but it was that he was with a few friends at a local bar after a concert. Friends were drinking, he wasn't. Ordered a single sandwich, tipped server 20% even tho they literally forgot him and never even refilled water glass. So let's say it was $10 + $2 tip. Total should have been $12.
The charge shows up a day later - $22. Somehow that $2 mysteriously had a "1" inserted in front of it. Making the tip higher than the total order. She must pull that crap all the time on latenight orders since most of the people in there are a bit drunk and likely won't remember exactly how much they ordered/tipped unless they are anal like we are.
We got freaked out for like 5 minutes, he located the bill, as he always writes down the total/tip on the extra copy and we wait to check it against the charge once it finalizes on our card online. Call the restaurant, speak with the manager. Explain that the waitress "mistakenly" added a ton of money to the tip line, and tell them this needs to be fixed. Manager apologies and tells him he will refund the whole thing but husband tells him to just change it to what it's supposed to be (give him a refund on the over-tip the waitress added "by mistake" and he'll be happy. Manager does so, because I suspect he could tell that the number was altered, or else they'd had complaints about this waitstaff before.
In any case, I'd suggest your first attack point is to contact the restaurant, with ticket in hand and politely but firmly insist that there were extras added to the order, likely they were for a table nearby and the waitress was confused/busy and got it on the wrong table. Insist (again, no namecalling/bitchy attitude, just explain firmly and politely that you are totally sorry you didn't notice this at the restaurant and it was so busy in there that it likely would be super easy for this sort of thing to happen, but you are very worried and concerned that you're being charged for items you didn't order/receive and can they please fix this?
If they flat out refuse, then you contact the card company, and dispute the charges. Brother is on shaky ground tho since he did have actual time to review the charges but didn't bother to do so carefully and still signed. All he can do is explain to the card issuer what you already said and ask them what they can do about it. It's fraud, and terrible and I hope you did name the actual waitstaff as well (if you don't get the restaurant to make it right) but you should have contacted the restaurant FIRST and given them a chance to fix things before blasting the hell out of them on social media sites. How are they to know and deal with a crappy employee if you don't give them the opportunity first?