At least he's having fun? I mean, he's not playing chess, but having fun is what really matters...unless you want to argue your point according to the rules of the game you're attempting to play...
I see nothing wrong with the attack. Others at a higher or lower level may disagree; it all depends on preference. I used that attack in a tournament only once, when I was p!ssed off after losing a game. I won.


Here are Two Main lines of the "Fried Liver Attack". It was first played by Polerio in 1590! Computer Analysis shows both lines as virtually even, no advantage even though White has Sacrificed a Piece! That is due to the Fact that White has plenty of compensation for that Knight.
If Black can carefully Defend... He is supposed to have the Advantage...lol Rubbish! The Databases will show you that White prevails most of the Time! It is easier to Attack than Defend. That is why people go to extremes to avoid defending this attack. I prefer to play the Ulvestad Variation with 5... b5!
There is a Fischer Variation where White plays d4 the move before the Knight Sacrifice, it is deadly!!
My take on this is, in the Main Lines, Black is best if he can trade down the Pieces! or Break the Pin and seek Shelter. White is Best to Complicate and Dogpile, Avoid the Exchanges!
'Fried Liver' Main Lines
Steinitz Variation
1. e4 e5
2. Nf3 Nc6
3. Bc4 Nf6
4. Ng5 d5
5. exd5 Nxd5
6. Nxf7 Kxf7
7. Qf3+ Ke6
8. Nc3 Ncb4
9. Qe4 c6
10. a3 Na6
Zukertort Variation
1. e4 e5
2. Nf3 Nc6
3. Bc4 Nf6
4. Ng5 d5
5. exd5 Nxd5
6. Nxf7 Kxf7
7. Qf3+ Ke6
8. Nc3 Nce7
9. O-O c6
10. Re1
Fischer
6. d4
Ulvestad Variation
1. e4 e5
2. Nf3 Nc6
3. Bc4 Nf6
4. Ng5 d5
5. exd5 b5
6. Bxb5 Qxd5
7. Bxc6+ Qxc6
8. O-O Bb7
9. f3 h6
10. Nh3 O-O-O
You write that it is rubbish that if black defends correctly he has the advantage because white's winning percentage is so high. But that means that black did not defend correctly.