Dear pradeep,

Now as your brother didn't uploaded the documents before the deadline, them his seat is cancelled and he is not eligible to attend further josaa rounds.
Now you cannot do anything. But there is one hope for getting nits, i.e, CSAB 2020.
As your brother got nit kurukshetra in first round then his rank must be upto the mark. And therefore he musy sit in csab round counseling, if he desperately want a nit. The csab will be held after josaa all round counselling. The offical dates are not released. Now, for participating in csab you must have to pay a participation fees of Rs. 36500 and if he got any seat and accepts it, then he have to pay Rs. 35000 as seat acceptance fees ( for general candidates).

So, there is still one hope remaining - CSAB.
Otherwise he can go for some other Private colleges because there is no chance that he can attend any furthur josaa round counselling.

Also check out the following link to know more about csab 2020 :-
https://engineering.careers360.com/articles/csab-special-round-for-nits-iiits-and-gftis