Cinderscape Draconian Traits

Blindsense: 5 feet based on smell

Breath Attack Recharge Rate: (Roll a 5 or 6) As a Free Action at the top of your turn after using the breath attack a prior turn, the player can role a d6 to recharge the breath attack. Out of combat, regain it every 30 seconds with DM approval.

If the player takes the fighter Blind Fighting Style the Blindsense & Blight Fighting combine:

You have blindsight with a range of 15 feet. Within that range, you can effectively smell anything (including things in total cover that aren't inside something), even if you're blinded or in darkness. Moreover, you can smell an invisible creature within that range, unless the creature successfully hides from you.