Yes, he can have a chance but he will have to study hard since there's just one month left and firstly you will have to go through the NCERT mainly chemistry. Chemistry would be a lot helpful because most of the questions would be coming  from that and there will be some facts that will have to be memorized. It will be good if you look first through the NCERT and then start doing the previous year papers of JEE Main. You also make notes of the facts mainly in chemistry which has to be memorized. It will be helpful because some questions might get repeated and solving papers will be the most helpful i think during the last month and since the exam is conducted in slots, you will have a lot of papers to practice and after doing some 10 papers, you will have an idea about the important topics.

Bojja Chetan Reddy
JEE 2019- AIR 21 IIT Madras CSE