He put the fracture level on 20 and he said he dont care
http://prntscr.com/6qq60

It is his server. He can do as he pleases. (of course farming and general infringement of rules is an exception)
That may not count as farming because if someone puts fracture low, there is still some degree of challenge and prevents instant wins.

was duel mode on? if so then it isn't really fair if the other person doesnt know he will just fracture himself.

Changing the settings in your server is allowed.

The only time it wouldn't be allowed is if you were dueling and didn't have your opponents' consent as to changing the game rules.

Ok ty.