Alzheimer's, the Eucharist, and The God Squad
The Eucharistic minister is right. Communion is not a blessing. I don't know what it means to say "Communion is not a blessing"; obviously Communion is a great blessing, so The God Squad must have some other notion in mind. But this is a question calling for precise answers, so let's use precise terminology.
Communion is an act of religious mystery and meaning that requires understanding. No, it does not require "understanding" (whatever exactly that means here); sure, reception (like most human acts) might be enhanced by the actor's level of "understanding", but that doesn't make "understanding" a requirement for reception of the Eucharist. Once admitted to Communion, a Catholic may not be denied the sacrament except for canonical cause. See 1983 CIC 18, 213-214, 843, and 912. (Don't just glance at those numbers, read the canons.)
Your mother's disease has robbed her of that necessary understanding that alone makes communion the supreme gift it is for believing Catholics. Alone? Alone? I doubt The God Squad meant it this way, but the statement they made is rank heresy. What makes Communion the supreme gift is not the "understanding" we accord it, but the fact that it is the Body, Blood, Soul, and Divinity of Christ. That reality is not in the slightest dependent on anyone's "understanding" of so great a mystery.
For this reason, communion is not given to children under 7. Sure it is, in the Eastern Churches all the time. Besides, we're not talking about a child here, but an adult. Once Roman Catholics are admitted to the Eucharist, they enjoy certain fundamental rights in regard to its reception, as outlined above. To withhold the Eucharist for reasons other than those given in law is to deprive the faithful of a fundamental right.
A child cannot be expected to understand what he or she is receiving. So? Besides the Eastern practice for Communion, an infant does not understand baptism; an unconscious person does not understand anointing. We don't withhold sacraments because of apparent deficient understanding.
What gave communion meaning for your mother before her illness was that she understood what she was doing and what she was receiving. This just rephrases what was so dangerously asserted earlier; so again, what gives meaning to the reception of Communion is the fact that it is the Body, Blood, Soul, and Divinity of Christ.
Now she apparently does not, and so it's really not fair to accuse the Church of abandoning your mother. I agree, it is not fair to blame the Church for the action of ill-informed Eucharistic minister, or for that matter, the answers of a Q&A group posting on the internet.
You and they can say the Lord's prayer with her. Sure, but I wonder, if the woman can still say the Our Father, how can she possibly be considered too mentally disabled to receive Holy Communion?
Religious rituals are not a right, they are a blessing and that blessing must be appropriately given. There is much confusion here: (1) religious rituals (here, sacraments) are most certainly a right of the faithful; (2) again, just how is the word "blessing" being used by The God Squad?; and (3) how is it "inappropriate" to give Communion to an elderly woman for reasons others than "The God Squad doesn't think it's appropriate"? Simply repeating an assertion doesn't make it correct.
We pray for your mother . . . May God heal [her] with a healing that is understood, if not by the mind, then perhaps by the soul. I don't think a discussion of the relationship between the mind and the soul is helpful, or possible, here.
In lieu of that, let's just accord an elderly Catholic woman her rights under canon law. If and when she fails to satisfy the requirements of ecclesiastical discipline (and nothing in the facts presented suggests she has failed to meet those requirements) , then we can and must withhold the Eucharist. And not otherwise.