Is it permissible to encourage a repentant person who had stopped praying to adopt the view of Ibn Taymiyyah regarding the non-obligation of making up missed prayers, and to suffice with supererogatory prayers, knowing that I personally follow the majority opinion regarding the obligation of making them up?

Prayer is a great pillar of Islam, and abandoning it carries a severe warning. One who abandons it, denying its obligation, is an infidel by consensus. As for abandoning it out of laziness, there is disagreement among scholars. The questioner should be congratulated on his steadfastness in prayer and his repentance for abandoning it. The majority view is to make up missed prayers if they were abandoned out of laziness, while Sheikh al-Islam Ibn Taymiyyah and those who agreed with him hold that making up intentionally missed prayers is not legislated; rather, the penitent should increase in supererogatory acts. The questioner should advise the one who abandons prayer and explain the sayings of the scholars to him, including the view of Sheikh al-Islam.