Is what was transmitted from Sheikh Ibn Uthaymeen—that whoever abandons prayer is an infidel who is not to be washed, prayed over, or buried in Muslim graveyards, and whose marriage contract is to be annulled—correct?

Abandoning prayer is one of the greatest sins by the consensus of Muslims, and it is more severe than adultery, theft, drinking alcohol, and murder. The disagreement regarding the disbelief of one who abandons prayer is well-known. Sheikh Al-Uthaymeen holds that whoever abandons prayer entirely is an infidel who will abide eternally in Hellfire, and this entails rulings of disbelief, such as separation between spouses, not praying over him, not burying him in Muslim cemeteries, and depriving him of inheritance. As for one who prays sometimes, this ruling does not apply to him, according to the Sheikh. The majority opinion is that abandoning prayer does not constitute disbelief that expels one from the faith.