let (someone) fly

Translations
дать волю (кому-то)
When he started the argument, she let him fly.
Когда он начал спор, она дала ему волю.
Definitions
To allow someone to act freely or independently, often by giving them permission or not restricting their actions; can also mean to let someone go or leave, sometimes used in the context of letting someone pursue their own path or make their own decisions.