They believe he is a mighty prophet a wise teacher born of a virgin , performed miracles like curing the leoper and the blind and overall a very special human in a very high status. They believe he will return again to kill the antichrist and unite christians , Jews , muslims into day of judgement and after he will get married and die a natural death. What they dont believe is that he is the son of God because God is above his creation so he cant have a son, he is above that. If you mean son in a figurative way like we are the children of God sure, but not the literal son of God. They don't believe he is God because God can't be a human he is above humans unimaginable nothing like him exists and he is one has no father no mother no kids he is the greatest. There are miracles in the quran about jesus that do not exist in the bible like when he was a baby he would speak to defend his mother when ppl accused her of adultary when she brought jesus to the town and other miracles.