How can one help one's brother with purification, prayer, and achieving devotion therein?

Prayer holds a great status in Islam, and it is the first act of a Muslim that will be examined. Severe warnings have been established concerning its abandonment or negligence. Deliberately abandoning prayer is considered disbelief by the consensus of scholars. As for abandoning it due to laziness or negligence, there is a difference of opinion, with the majority holding that it does not amount to disbelief. Purity (Tahara) is a condition for the validity of prayer; it is its key. It must be noted that prayer is not valid without purity. Humility (Khushoo') is the fruit and benefit of prayer, and the worshiper should be mindful of the greatness of Allah Almighty. However, prayer is valid without it according to the majority. Your brother must immediately make up all the prayers he missed, to the best of his ability. If he does not know their number, he should continue making them up until he is reasonably certain that he has fulfilled his obligation.