Tell your friend about these passages about Jesus after He had risen from the dead:
24 Now Thomas, called the Twin, one of the twelve, was not with them when Jesus came. 25 The other disciples therefore said to him, “We have seen the Lord.”
**So he said to them, “Unless I see in His hands the print of the nails, and put my finger into the print of the nails, and put my hand into His side, I will not believe.”
26 And after eight days His disciples were again inside, and Thomas with them. Jesus came, the doors being shut, and stood in the midst, and said, “Peace to you!” 27 Then He said to Thomas, “Reach your finger here, and look at My hands; and reach your hand here, and put it into My side. Do not be unbelieving, but believing.” **
28 And Thomas answered and said to Him, “My Lord and my God!”
29 Jesus said to him, “Thomas, because you have seen Me, you have believed. Blessed are those who have not seen and yet have believed.”
36 Now as they said these things, Jesus Himself stood in the midst of them, and said to them, “Peace to you.” 37 But they were terrified and frightened, and supposed they had seen a spirit. 38 And He said to them, “Why are you troubled? And why do doubts arise in your hearts? 39 Behold My hands and My feet, that it is I Myself. Handle Me and see, for a spirit does not have flesh and bones as you see I have.”
40 When He had said this, He showed them His hands and His feet. 41 But while they still did not believe for joy, and marveled, He said to them, “Have you any food here?” 42 So they gave Him a piece of a broiled fish and some honeycomb. 43 And He took it and ate in their presence
I’ll leave up to someone more knowledgeable to talk about the assumption of Mary. However, the Catechism states:
966 "Finally the Immaculate Virgin, preserved free from all stain of original sin, when the course of her earthly life was finished, was taken up body and soul into heavenly glory, and exalted by the Lord as Queen over all things, so that she might be the more fully conformed to her Son, the Lord of lords and conqueror of sin and death."508 The Assumption of the Blessed Virgin is a singular participation in her Son’s Resurrection and an anticipation of the resurrection of other Christians:
In giving birth you kept your virginity; in your Dormition you did not leave the world, O Mother of God, but were joined to the source of Life. You conceived the living God and, by your prayers, will deliver our souls from death.509
508 LG 59; cf. Pius XII, Munificentissimus Deus (1950) : DS 3903; cf. Rev 19:16.
509 Byzantine Liturgy, Troparion, Feast of the Dormition, August 15th.
Catechism quoted from here