There is a grain of truth to the first passage being about Muhammad, but just a very small grain. Let me explain. The Bible makes it plain that Abraham’s first son by Hagar, Ishmael, was the father of the Arabs. Muhammad was an Arab, and therefore, according to Genesis 21:13-21, he would be a descendant of Ishmael. However, there is not the slightest indication of Muhammad in this passage. Where does this passage say that one particular descendant of Ishmael will rise up as a prophet? It simply is not there. Abraham sent Ishmael away because he was the son of a slave woman and was not to be the father of the nation Israel. He was not to be the ancestor of the Messiah. Nevertheless, Abraham blessed Ishmael. But, again, there is literally zero indication in this passage of some sort of prophet coming from Ishmael. What it says is that God will make Ishmael into a great nation. Well, God has done that! Again, there is not the slightest indication of Muhammad there. I would challenge your friend to present his case from this passage. He will not be able to do so.
Isaiah 41:11 says this: Let the wilderness and its towns raise their voices: let the settlements where Kedar lives rejoice. Let the people of Sela sing for joy; let them shout from the mountaintops. OK, where is this a prophecy about Muhammad? This is really silly. By the way, the Kedarites/Quedarites were ancestors of the modern Arabs, as were the people of Sela, and I am glad that God is telling them to rejoice. But what possible indication is this of a prophet to come among the Kedarites? This is an outright fabrication. To say that it is clearly a prophecy about Muhammad is to tell a bald-faced lie.
The first passages are about the descendants of Ishmael and they project a positive idea about them. The third passage is a prophecy against the Arab peoples. It is a prophecy that they will be taken by the sword and that all their splendor will come to an end. The first two are obviously not a prediction about Muhammad, but who in their right mind would even consider the possibility that this prophecy condemning the Arab peoples of Kedar could be a “clear prophecy” about Muhammad?
This shows how desperate these Muslims are to claim that Muhammad fulfills Old Testament prophecy. To resort to using passages that anyone in their right mind would know has nothing to do with Muhammad shows that Muslims are really grasping at straws here. Don’t they have anything better than this? Are they expecting a Jew of a Christian to agree with this crazy interpretation? Please, do not be confused. It is clear what is going on here.
Compare this supposed evidence of prophecy about Muhammad to Psalm 22:16-18 “they have pierced my hands and my feet,” or to Isaiah 53:1-12 “He was despised and rejected by men,” “He was pierced for our transgression.” or Micah 5:2 “But you, Bethlehem… out of you will come one for me… whose origins are from old…” Ask anyone in the world, even if they are not Christian, what these prophecies are about, and they will know immediately they are about the man known as Jesus of Nazareth. Compare that to these passages your Muslim friend is using, for which literally no one would think of Muhammad unless they were told to–even Muslims, and you can see what is going on here. Please ignore this bogus claim and help your Muslim friends to know how truly bogus it is.