Your dearly departed, by your own vain idea, are in Purgatory at best and maybe worse, for all you know. They aren’t helping anybody, they can’t even help themselves. Jesus said that there is a great gulf between the living and the dead. Again, you obstinately refuse to pray to the One who demands obedience above all things.
Your imprecision in this conversation is indicative of your level of ignorance on the subject. No where did I mention anything about my "dearly departed". This isn't about praying to "Grammy" or my dear Aunt Agnes. This is about intercessory prayers to saints. Saints, by definition are those already in heaven.
The Bible directs us to invoke those in heaven and ask them to pray with us.
Thus in Psalms 103, we pray, "Bless the Lord, O you his angels, you mighty ones who do his word, hearkening to the voice of his word! Bless the Lord, all his hosts, his ministers that do his will!" (Ps. 103:20-21). And in Psalms 148 we pray, "Praise the Lord! Praise the Lord from the heavens, praise him in the heights! Praise him, all his angels, praise him, all his host!" (Ps. 148:1-2).
Not only do those in heaven pray with us, they also pray for us. In the book of Revelation, we read: "[An] angel came and stood at the altar [in heaven] with a golden censer; and he was given much incense to mingle with the prayers of all the saints upon the golden altar before the throne; and the smoke of the incense rose with the prayers of the saints from the hand of the angel before God" (Rev. 8:3-4).
And those in heaven who offer to God our prayers arent just angels, but humans (saints) as well. John sees that "the twenty-four elders [the leaders of the people of God in heaven] fell down before the Lamb, each holding a harp, and with golden bowls full of incense, which are the prayers of the saints" (Rev. 5:8). The simple fact is, as this passage shows: The saints in heaven offer to God the prayers of the saints on earth.