Yes - at the moment of our death we will stand before God and either receive salvation or damnation …
However, - even for the man’s uncle who committed suicide - it is impossible for us to determine what transpired between them and God at the moment of their death …
The person who rejects God and takes their life could repent before their death … or not

we cannot know this with any certainty … all we can do is look at the outward signs - not the full reality.
A person could seem to be rejecting God by killing themselves - but they maybe free of sin because they may not meet the criteria -
1] Serious nature of the sin - Grave matter - suicide is a grave matter,
2] Fully aware of the sinfulness of the act - knowing that suicide is sinful
3] Freely and fully decide to commit the sinful act - suicide
It is possible that a person who is mentally ill may not meet all three - and it is impossible for us to know if all three existed … mental illness is real, just as cancer is real …
Thankfully - We entrust our souls to an All Knowing, Loving and Just Judge - who does fully - completely know our hearts and our lives