What is the reason a young man is unable to continue praying after committing to it for a short period, and how can he persevere in it?

Neglecting prayer is a grave matter. Some scholars consider it a major disbelief (kufr akbar), while others view it as one of the greatest major sins (kaba'ir).

Among the things that help maintain prayer are: 1. Going to the mosque to perform congregational prayers. 2. Accompanying the righteous and avoiding the wicked. 3. Changing one's residence and environment if they do not facilitate performing prayers. 4. Remembering the virtues and greatness of prayer, and the sin of one who abandons it.