So as we all know the fork is happening
no we don't know that with certainty.
Once BTC splits into BTU
who said BTC is going to split and who said it is going to split into BTU?!!
And should I buy more btc right now it's not for holding I will be investing into alt coins
seems to me like you are certain about things that everybody doubts about (things like fork and split, and investing in pump and dump altcoins, ...) but you are doubt things that others are more certain about (things like buying bitcoin or not)!