Is my friend barred from joining the Church because he is a Freemason?
The short answer
He can become Catholic if he leaves Freemasonry. Catholics are forbidden to belong; the Church's negative judgment on Masonic associations is unchanged, and Catholics who join are in a state of grave sin and may not receive Communion.
Leaving Freemasonry
If he plans to give up Freemasonry for Catholicism, he can certainly become Catholic.
Remaining a Mason
Catholics are prohibited from involvement in Freemasonry, so if he intends to remain a Mason he cannot enter the Church.
The Church's judgment
The Declaration on Masonic Associations states that the Church's negative judgment remains unchanged, because their principles have always been considered irreconcilable with Church doctrine. Membership remains forbidden, and the faithful who enroll are in a state of grave sin and may not receive Holy Communion.