Shalom! my mother is giving money to some businessmen in agriculture as borrow and they give her 12 % when they collect the harvest. Please advise me what are the laws of it? even if they are goyim but giving money on percentage is forbidden? I don't want to fight with mother but how should I act or behave? and is it possible to receive like profit from harvest in the form of harvest, not cash? please advise how is it from Halacha?

ב"ה Shalom I do not have enough details of the business deal with the goyim. So I can only answer you in general lines. If your concern is taking "ribit"= interest from a goy, the Shuclan Aruch (Yoreh De'ah 159:1) says that it is permitted. Though with the little details given , I am not sure if there is interest here at all. What is more important is the clear Mitzvah of the Torah of respecting parents. The Talmud (Kiddushin 32a and it is codified in the Shulchan Aruch Yoreh De'ah 240:11) writes clearly that if one sees his father (but it refers to both parents) transgressing, he may not tell him "You are going against the words of the Torah." But he can say, as if reminding him or asking him "Doesn't it say in the torah such and such?" so as not to cause embarrassment to the parent. If the parent is ignorant of Torah law, then one may describe the prohibition in a story like fashion about a certain case when somebody did such and such and the Rabbi said it was forbidden so they can understand on their own and make the correct conclusions. All the Best