بسم الله الرحمن الرحيم
Those Muslims who insist Jesus of Nazareth was raised to Heaven alive in his body quote from the Quran, Surah 3:55:
اِذۡ قَالَ اللّٰہُ یٰعِیۡسٰۤی اِنِّیۡ مُتَوَفِّیۡکَ وَ رَافِعُکَ اِلَیَّ
When Allah said, ‘O Jesus, I will cause you to die and raise you to Myself’
Firstly, it should be noted that the rafa (ascension) of Jesus is to occur after his wafah (death), and that clearly indicates a spiritual ascension, when the soul is taken from the body by the Angel of Death and he ascends with it into Heaven.
Secondly, Imam Fakhruddin al-Razi has explained that the rafa of Jesus as spoken of in 3:55 is not the rafa of the body, or an ascension in terms of place and direction:
وَاعْلَمْ أَنَّ هَذِهِ الْآيَةَ تَدُلُّ عَلَى أَنَّ رَفْعَهُ فِي قَوْلِهِ وَرافِعُكَ إِلَيَّ هُوَ الرِّفْعَةُ بِالدَّرَجَةِ وَالْمَنْقَبَةِ، لَا بِالْمَكَانِ وَالْجِهَةِ، كَمَا أَنَّ الْفَوْقِيَّةَ فِي هَذِهِ لَيْسَتْ بِالْمَكَانِ بَلْ بِالدَّرَجَةِ وَالرِّفْعَةِ
Know that this Ayah [3:55] proves that his raising, in the saying “And raise you to Myself” is the raf’ah of rank and status, not place and direction (Tafsir al-Kabir; v.8, p.77, published by Darul Fikr):