For we are not to despair of anyone so long as the patience of God leads the ungodly to repentance, and does not seize him out of this life . . .
Augustine, Sermon LXXI, xiii, 21.
Have you given up on the conversion of your husband? Your child? Your relative? Your neighbor?
You must not do so. You do not know that God has done so. He/she may yet be converted. Perhaps on the death bed; perhaps before. But it is your task not to make a final judgment about anyone. God, alone, knows the heart.
Your task is, however, to keep on praying for him, to keep on witnessing to him, to keep on living a godly life before him.
Yes, I know it seems unlikely that he or she would ever believe. But didn’t it seem even more unlikely that Saul of Tarsus would become the apostle Paul?
Who are you to judge that the eternal destination of another will not be heaven—while the door to it still stands open? While the door stands open, your mind must as well.
No. If you have given up hope, it is time to renew it. Talk to the Lord about the matter. Tell Him you believe that His power is greater than any the evil one exerts over your unsaved friend. Beg Him to save him. Then tell Him you will be satisfied with the outcome.