Most Baha'i prayer books have a section on prayers for those who have passed away from this "world of dust", or you can go here to find lots of them. Remember that only the Prayer for the Dead is obligatory and must be said in accordance with instructions.
Writings on the life after death and immortality are appreciated by just about everybody, whether they are Baha'is or not. Here are a few:
O SON OF THE SUPREME! I have made death a messenger of joy to thee. Wherefore dost thou grieve? I made the light to shed on thee its splendour. Why dost thou veil thyself therefrom?
'Abd'ul-Baha grieved for His Father even as we grieve for those we love who have left us, but He says: "...I am consoled by the realization that the worlds of God are infinite; that though they were deprived of this existence, they have other opportunities in the life beyond, even as Christ has said, "In my Father's house are many mansions." They were called away from the temporary and transferred to the eternal; they abandoned this material existence and entered the portals of the spiritual world. Foregoing the pleasures and comforts of the earthly, they now partake of a joy and happiness far more abiding and real, for they have hastened to the Kingdom of God."
Baha'is believe that life goes on and can't, in fact, be extinguished. Baha'u'llah says:
"The world beyond is as different from this world as this world is different from that of the child while still in the womb of its mother. When the soul attaineth the Presence of God, it will assume the form that best befitteth its immortality and is worthy of its celestial habitation. Such an existence is a contingent and not an absolute existence, inasmuch as the former is preceded by a cause, whilst the latter is independent thereof. Absolute existence is strictly confined to God, exalted be His glory. Well is it with them that apprehend this truth. Wert thou to ponder in thine heart the behavior of the Prophets of God thou wouldst assuredly and readily testify that there must needs be other worlds besides this world."
If we are faithful to God we will find ourselves closer to Him than if we are careless and self-serving.
O SON OF MAN! The light hath shone on thee from the horizon of the sacred Mount and the spirit of enlightenment hath breathed in the Sinai of thy heart. Wherefore, free thyself from the veils of idle fancies and enter into My court, that thou mayest be fit for everlasting life and worthy to meet Me.