They maybe able to do if recent and i guess your bf didn't for what ever reason have the eticket or a e receipt emailled to him?
For example on expedia which i use even for a certain amount of time i can download an eticket/filght details of our filght.
But don't panic to much about tickets if you dont have them, trust me the passport stamp/photos is far more proof than a ticket or stubs. The passport stamp even says what filght you were on. If the photos are shown from a few trips ie haircut/style have changed, tans of us brits is differnt ie pale in the winter and not so pale in the summer. If you have pictures in various locations they will be far more satisfied you have indeed met and spend time together.
From the little checklist My wife recieved in her jiffy bag back with the evidence and passport from embassy i don't recall tickets or boarding cards being a thing they had to see proof of.
But passport and photos were.