In the House of the Dragon season 1 conclusion, Daemon eventually learns about Aegon's dream, but his response shows that Viserys made the right choice by keeping it a secret.

Rhaenyra informs Daemon that her oath extends beyond her own personal ambition to the Song of Ice and Fire as she examines Alicent's peace proposal.

Since Viserys didn't trust Daemon with it or think he would give it the attention it demanded, Aegon's dream was kept a secret from him.

Due to Daemon's intense personal ambition over his responsibility to the realm and humanity, Viserys never made him his Hand or his heir.

Contrarily, the 14-year-old Rhaenyra was aware of her obligations despite her rebellious tendencies, and she never genuinely desired to be Viserys' successor; instead, she yearned for her father to have a son in the first episode of House of the Dragon.

The fact that only Rhaenyra was informed about Aegon the Conqueror's dream shows that Viserys placed the responsibility of it in the correct hands because Daemon would never have taken it seriously.

Upon discovering the dream, Daemon most likely would have had even less respect for his brother and may have allowed the prophecy's weight to pass along with him.

Upon discovering the dream, Daemon most likely would have had even less respect for his brother and may have allowed the prophecy's weight to pass along with him.

Upon discovering the dream, Daemon most likely would have had even less respect for his brother and may have allowed the prophecy's weight to pass along with him.