Cross-compare to other places Paul uses the term ‘works’ in regards to faith.
Romans 3:28: For we hold that a man is justified by faith apart from works of the law.
Galatians 2:16: yet who know that a man is not justified by works of the law but through faith in Jesus Christ, even we have believed in Christ Jesus, in order to be justified by faith in Christ, and not by works of the law, because by works of the law shall no one be justified.
In other places, Paul sets up faith as opposed to works of the old Jewish law. Same thing in Ephesians, although he doesn’t explicitly add ‘of the law’.
Also, faith without works would be a direct contradiction of James 2:14-26, where he says having faith but not having the works to back it up, is dead.
You might also ask your friend about Ephesians 2:10 (which he/she conveniently doesn’t quote): 8 For by grace you have been saved through faith; and this is not your own doing, it is the gift of God— 9 not because of works, lest any man should boast. 10 For we are his workmanship, created in Christ Jesus for good works, which God prepared beforehand, that we should walk in them.
Faith and works here are actually unified in verse 10, just like they are in James Ch. 2. Also, remember here that he points out ‘not works, so that men don’t boast.’ It was common for the Pharisies to stand up and make a show of their piety in the synagogue or on the street. Again, a subtle reference here to the works referred to by Paul being those ‘of the law’.