They do lack the fullness of truth in the CS church and need our prayers and evangelization.
From Catholic Sign article by Father Robley Whitson and Pam Robbins:
"For those who stand outside it, Christian Science is a religion shrouded by mysterious metaphysics and obscured by two major misconceptions: that it is a faith-healing cult and/or that it is one more branch on the tree of Protestantism.
“In reality, it is neither. And while it is radically different from Catholicism (and from Protestantism as well) in both form and content, it can teach us much about the endless possibilities that exist for human beings who seek - and find - God. . .”
“With her initial realization of Christian Science in 1866, Mary Baker Eddy synthesized many and varied elements in her life to formulate a religion, eventually so well integrated that it has stood virtually unaltered since her death in 1910. Its survival is especially noteworthy in light of the controversy and opposition it engendered from its inception. People often mistrust what they do not understand and Christian Science, with its emphasis on the spiritual and negation of the physical, its patent refusal to rely on medicine, and its departure from traditional Christian positions, seemed to some an enigma and a threat. . .”
“Over the past century, Christian Science has earned respect, first by sheer longevity (time tends to lend respectability to the most radical movements and philosophies), by the journalistic world leadership exercised by Mrs. Eddy’s best known undertaking, The Christian Science Monitor, and by the simple, quiet dignity of its churches, its publications and its members’ lives. . .”
"Still, it is fair to say that, across the board, Christian Science is little understood and, worse, often misunderstood. Its truths are neither easily synopsized nor quickly communicated. Yet, Mrs. Eddy’s scientific system of faith is precisely a *system, *capable of being intellectually grasped. A Scientist, or active member, is always thought of as a student, and reads and studies daily, confident that God is knowable, as revealed through the Bible as interpreted by Mrs. Eddy’s textbook, Science and Health with Key to the Scriptures. . ."
“The first century of its existence has indicated that Christian Science is not a universal call, and its adherents must explore ways in which they can leaven society and maximize their influence and impact. It is important for us as Catholics (and, ecumenically, to all Christians) that they do, lest we be deprived of what they have to offer - and they have much to offer us. . .”
“First of all, as with all other religious systems, there is the gift of heightened perspective that comes from taking a long look at something different. Regardless of how unexpected some stances are, at the very least they help us to see what divergent possibilities exist. A system like Christian Science, so pragmatic, so scientific - and so fascinatingly American - can prod us to rethink what we believe, not that we might reject or revise it, but that we might invest it with richer meanings, and see it in new dimensions. . .”
"No sketchy analysis of Christian Science, however respectful or well-intentioned, can communicate it adequately, any more than the nuances of Catholicism could be captured for non-Catholics in a single written effort. But even an overview can suggest some of the uniqueness of the faith and an awareness of the amazing gift that was Mary Baker Eddy’s. A simple New Englander of eclectic education, she set forth truths she believed were divinely revealed to her through intense study and reflection, and articulated them with such care and thoroughness that they bear fruit a century later.
Much maligned in her lifetime, she is remembered today for the words she wrote and the Church she founded. Whatever the present and future state of Christian Science, Mrs. Eddy contributions cannot be underestimated. If she changed a single life, she may have changed thousands of lives, and in either case, who can say she did not change the world? As she said herself, ‘It is of comparatively little importance what a man thinks or believes he knows; the good that a man does is the . . . sole proof of rightness.’"