[quote="shanishani7, post:1, topic:
I know prayer for the soul of a Catholic is helpful for getting out from Purgatory to Heaven, and I always pray for the poor holy souls. But, I am not sure about those who never baptised, and even not sure about the baptism in Protestant church.
In my knowledge, only Catholics (those who baptised in Catholic Church) can get to heaven…
You’re understanding is lacking:
From our Catholic Catechism:
1783 Conscience must be informed and moral judgment enlightened. A well-formed conscience is upright and truthful. It formulates its judgments according to reason, in conformity with the true good willed by the wisdom of the Creator. The education of conscience is indispensable for human beings who are subjected to negative influences and tempted by sin to prefer their own judgment and to reject authoritative teachings
WHO CAN BE SAVED?
846 How are we to understand this affirmation, often repeated by the Church Fathers? Re-formulated positively, it means that all salvation comes from Christ the Head through the Church which is his Body:
Basing itself on Scripture and Tradition, the Council teaches that the Church, a pilgrim now on earth, is necessary for salvation: the one Christ is the mediator and the way of salvation; he is present to us in his body which is the Church. He himself explicitly asserted the necessity of faith and Baptism, and thereby affirmed at the same time the necessity of the Church which men enter through Baptism as through a door. Hence they could not be saved who, knowing that the Catholic Church was founded as necessary by God through Christ, would refuse either to enter it or to remain in it.
847 This affirmation is not aimed at those who, through no fault of their own, do not know Christ and his Church:
Those who, through no fault of their own, do not know the Gospel of Christ or his Church, but who nevertheless seek God with a sincere heart, and, moved by grace, try in their actions to do his will as they know it through the dictates of their conscience - those too may achieve eternal salvation.
848 “Although in ways known to himself God can lead those who, through no fault of their own, are ignorant of the Gospel, to that faith without which it is impossible to please him, the Church still has the obligation and also the sacred right to evangelize all men.”
Because we CANNOT know fully the mind and heart [Mercy] of GOD [Isa 55: 6-9 ]  Seek ye the Lord, while he may be found: call upon him, while he is near.  Let the wicked forsake his way, and the unjust man his thoughts, and let him return to the Lord, and he will have mercy on him, and to our God: for he is bountiful to forgive.  For my thoughts are not your thoughts: nor your ways my ways, saith the Lord.  For as the heavens are exalted above the earth, so are my ways exalted above your ways, and my thoughts above your thoughts"
So YES, do pray for that soul. No prayers goes to waste.