[Machine] Prayer is not appropriate for anyone except the Prophet. The Sheikh means by this the prayer that is a greeting to his remembrance with great respect. As for his prayer for others, it was in the sense of supplication and blessing, and that is permissible for others.
مَا يَنْبَغِي الصَّلَاةُ مِنْ أَحَدٍ عَلَى أَحَدٍ إِلَّا عَلَى النَّبِيِّ ﷺ قَالَ الشَّيْخُ يُرِيدُ بِهِ الصَّلَاةَ الَّتِي هِيَ تَحِيَّةٌ لَذِكْرِهِ عَلَى وَجْهِ التَّعْظِيمِ فَأَمَّا صَلَاتُهُ عَلَى غَيْرِهِ فَإِنَّهَا كَانَتْ بِمَعْنَى الدُّعَاءِ وَالتَّبْرِيكِ وَتِلْكَ جَائِزَةٌ عَلَى غَيْرِهِ