If someone passes away, how do we tell if he is in the state of Janabat? The reason for asking this question is because the ghusl of a dead person who is in the state of janabat will be different. So, how would we wash him when we don’t know his condition?
بِسْمِ اللهِ الرَّحْمنِ الرَّحِيْم
In the name of Allah, the Most Gracious, the Most Merciful
This situation primarily applies in the time of war when a person is martyred and was in a state of janaabah. Imam Quduri says: “When a junub is killed [as shahid], he is given a ghusl according to Abu Hanifah.” Therefore, this probably does not apply in your situation. However, the way to ascertain it is by someone, such as his wife, informing you that they were intimate and he is in a state of janaabah.
Only Allah knows best
Written by Maulana Mustafa Umar
Checked and approved by Mufti Mohammed Tosir Miah
Darul Ifta Birmingham
 Mukhtasar Al-Quduri p. 80, Taha Publishers, 2010