[Modern] Untitled Deck

[DavidCkuhn]

Untitled Deck

Need pointer on how to make this a better deck and an improved strategy would be nice. please be helpful, and kind, because my little brother is 8 years old and he made this him self.

[Yisan, The Wanderer Bard]

Gaining life? Why not gain even more!? Rhox Faithmender makes any life gain twice as fun (effect also available as an enchantment, Boon Reflection, and soon a Legendary artifact, Alhammerret's Archive). And with all that life, why not spend a pretty penny and play a few copies of Felidar Sovereign? Obvious downsides to life gain as a strategy are that players might not be trying to win with damage or in a linear fashion (Mill, combos, or infect) which is partly why life gain is considered 'generally' weak.
Other suggestions? Go for consistency. The removal package needs to hit a lot of things. Replace cards like Rebuke with multiple copies of Devouring Light. Also consider Oblivion Ring as it hits just about everything.
With the creatures too, consistency is important. I know you want to play all the things with flying, but often picking the best two or three and running 3 or 4 copies is better.
Making tokens seems to be a fair part of the deck. Martial Coup or Secure the Wastes might amp that game a bit. Then pair with 5 or 6 anthem cards so you are getting more damage in from each creature. Anthems like Crusade are cheap, but Spear of Heliod and Hall of Triumph are one-sided.
Hope your brother continues to play and learn the game of Magic. (With or without my suggestions )