All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad (ﷺ) is His Slave and Messenger.
We ask Allah to reward you and to make you a source of benefit. However, this suggestion may confuse the young man regarding his religion, leading him to think that there is a legitimate concession allowing such gradual practice, whereas he is required to perform all five daily prayers in every circumstance as long as he is of sound mind.
What is obligatory is that you make clear to him that the prescribed prayers are five, none of which may be omitted under any circumstance so long as he remains mentally sound. Nevertheless, limiting himself to performing two prayers—while acknowledging the obligation of all five—is less sinful than abandoning the prayers altogether.
Allah Knows best.