If he carved in mom's oak table I'd be giving him a size 11 boot up his azz for Christmas! And your "friend"?.... some friend. OK, call them both into the room with mom.
AFTER they profusely apologize to her and they make a believer out of her, have them empty their pockets. Take all their money and drive their sorry assses down to Lowe's and get some sandpaper, some matching putty, a package of stain wipes and a small can of sealing lacquer that matches the original finish. Have the two miscreants personally perform the repairs.
Then ban them from the kitchen for a month and never ever let them touch the table ever again UGH! I hate young morons with no moral compass.
Your best bet is to tell your mom right away. She will find it eventually then you will really be in trouble. If it's really solid oak and the carvings aren't that deep you might be able to have it sanded down and refinished... but you are talking some serious money.
You might be able to get a stain pen, or crayon in a similar color and cover the scratches but that won't do much but hide the scratches visually... she'll feel them at some point. But seriously... I would tell your mother exactly what happened.
I commend you for wanting to undo the damage your little brother and your friend did. The only things I can think of that would make the scratches less obvious are either a matching furniture crayon or matching wood putty, depending on how deep the scratches are. If they're superficial, then the crayon will work.
If they're really deep, the gouge needs to be filled with wood putty. Just understand, these won't get rid of the damage, they'll just make the damage less visible and obvious.
I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.