All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger.
Residence in non-Muslim countries is a disaster that has become common among Muslims, to the extent that they fight for it and spend a great deal of money for this purpose.
First, we ask Allaah The Almighty to forgive this person who committed suicide and expiate his sins.
Ignorance of Islamic rulings is the greatest danger that afflicts immigrants from Islamic countries to non-Muslim countries, especially those who settle and live there permanently. Even worse, there are many other serious consequences that cannot be foreseen by such immigrants because there is no one to draw their attention to them, while the person is ignorant of these issues himself. One example of this is abandoning prayer or neglecting it. What happened to this person is a clear example of this.
Nevertheless the Prophet, sallallaahu ‘alayhi wa sallam, once supplicated to Allaah The Almighty to forgive a man who had committed suicide. [Muslim] An-Nawawi deduced from this Hadeeth that it is not permissible to call a person who commits suicide a disbeliever.
Therefore, supplication for a person who commits suicide is permissible, as they are not considered a disbeliever. Such a person is under the will of Allaah The Almighty, so Allaah The Almighty will punish him if He wills, or forgive him if He wills.
Allaah Knows best.