Yes, like others have said, one is not ready to join the Church until you are ready to accept every teaching of the faith. If the Church is wrong on any one issue, the entire faith collapses. Why should we trust the Church when she says that Matthew is part of the Canon, for example, if she is wrong about our Lady?
I would suggest that this friend of yours pray, pray, pray…and talk to a good, orthodox priest, with a healthy devotion to our Lady. I’m a former Evangelical myself, not yet confirmed even…but I’ve been fostering a devotion to our Lady over the last several months, and find her an ever present advocate…a loving, kind, and unfailing mother.
Has your friend read the Marian paragraphs in the Catechism? There are a number, just look in the index under “Mary”. I’d like to share 964 and 971.
964
*Mary’s role in the Church is inseparable from her union with Christ and flows directly from it. “This union of the mother with the Son in the work of salvation is made manifest from the time of Christ’s virginal conception up to his death”;504 it is made manifest above all at the hour of his Passion:
Thus the Blessed Virgin advanced in her pilgrimage of faith, and faithfully persevered in her union with her Son unto the cross. There she stood, in keeping with the divine plan, enduring with her only begotten Son the intensity of his suffering, joining herself with his sacrifice in her mother’s heart, and lovingly consenting to the immolation of this victim, born of her: to be given, by the same Christ Jesus dying on the cross, as a mother to his disciple, with these words: "Woman, behold your son."505* (As quoted from
usccb.org/catechism/text/pt1sect2chpt3art9p6.htm…
References 504 and 505:
LG 57.
LG 58; cf. Jn 19:26-27.
971:
“All generations will call me blessed”: "The Church’s devotion to the Blessed Virgin is intrinsic to Christian worship."515 The Church rightly honors "the Blessed Virgin with special devotion. From the most ancient times the Blessed Virgin has been honored with the title of ‘Mother of God,’ to whose protection the faithful fly in all their dangers and needs. . . . This very special devotion . . . differs essentially from the adoration which is given to the incarnate Word and equally to the Father and the Holy Spirit, and greatly fosters this adoration."516 The liturgical feasts dedicated to the Mother of God and Marian prayer, such as the rosary, an “epitome of the whole Gospel,” express this devotion to the Virgin Mary.517
References 515-517:
Lk 1:48; Paul VI, MC 56.
LG 66.
Cf. Paul VI, MC 42; SC 103.
(Catechism of the Catholic Church, English translation)
The Catechism is online at
usccb.org/catechism/text/index.htm, if you don’t have one. The Marian references are:
829
773
973
965
963-972
964
2030
273
966
974
487
485
509
723
971
490
488-93
508
491-492
721
968-970
975
493
507
495
721
967
144
494
511
2617-2619
722
484
411
496-507
510
506
502-506
499
497-498
500
(sorry they are in a weird order, I just typed them in from the index, which told you the specific Marian point addressed in each paragraph).