How prayer works
Yes God may not give a blessing because a certain person didn’t prayed. That’s why we ask Christians to join us in prayer for peoples’ health, preventing disasters, and things like that that are very important.
Praying for a dead person is part of mourning and part of glorifying God for giving life but it doesn’t change where the deceased goes. Praying for the soul of a nonchristian hoping that it will get him into heaven in pointless.
If a blessing may only be given if a certain person (or people) pray, and large numbers of prayers are said to increase the chances of a prayer being answered, then does this mean that popular and famous people have a better chance of receiving blessings from God than lonely people who have nobody to pray for them?
Thank you for the clarification on praying for the dead. That answered my question.