Do you know her pastor?
I understand that we need to do things as family with other Jesus people. You said people you know told you about her. So, you can stay with acting with people you know are spiritual > > > Galatians 6:1, Hebrews 5:2, James 5:16. And you can do what you find God guides you to do with each other. Trust each other and do pray, and stay with doing precisely what God satisfies and encourages you to do in His peace, and see how well He works this out.
Stay with good example . . . in the sight of God >
"nor as being lords over those entrusted to you, but being examples to the flock." (1 Peter 5:3)
And pray the way God has us pray > Philippians 4:6-7 >
"and the peace of God, which surpasses all understanding, will guard your hearts and minds through Christ Jesus." (Philippians 4:7)
If she prays the way God has her pray, her spiritual mind will be kept by God's own peace, even while she may have physical brain and other infirmities. This apparently worked for Paul our example > 2 Corinthians 12:7-15. Once Paul was doing things in God's grace he could take "pleasure" in his "infirmities".
Be an example of this for her, so this can feed her. You can be the scripture (2 Corinthians 3:3) to encourage her
I'm not talking about physical brain function, here, but "be renewed in the spirit of your mind." (in Ephesians 4:23) God's spiritual peace is in His power almighty to keep our spiritual minds, even while we can have physical infirmities of our brains and other parts of our bodies. So, I understand it is good to pray with others and keep with being good examples of staying in His peace in our spiritual minds, and obey how our Heavenly Father rules us in our hearts >
"And let the peace of God rule in your hearts, to which also you were called in one body; and be thankful." (Colossians 3:15)
All God's children are "called in one body" to this; so this is a basic of being a Christian. Another basic, in case any of us is not obeying this, is Hebrews 12:4-11 < how our Father corrects all of us. We all need to actively seek our Father for the correction He knows we need, which He Himself does in us > producing "the peaceable fruit of righteousness" > and Hebrews 12:8 is very clear how He does this with all of us who are His children. This is spiritual correction, deeper than physical "infirmities".
Actually, if her pastor is a Christian and scripturally qualified to pastor > 1 Timothy 3:1-10 > I think it is his responsibility to take care of her, and Hebrews 13:17 says we are to obey those who are responsible for us. So, though, you can offer him things you know and offer to help along with him and his church; possibly God would have you go through your own pastor to contact him. Do things as family. Encourage her to share with you all as family >
"with all lowliness and gentleness, with longsuffering, bearing with one another in love, endeavoring to keep the unity of the Spirit in the bond of peace." (Ephesians 4:2-3)
And together you can tell, prayerfully, how she really is, and if she is being Christian family (Ephesians 4:31-32, Ephesians 5:1-2, Ephesians 5:21, Colossians 3:12-15) with you. But there are people who have their own idol of independence, and this can cut them off from the loving they can share. And I will offer > a person who is physically sick can still keep on loving, if he or she is a deeply and spiritually loving person > "Love does no harm to a neighbor," we have in Romans 13:10. But, of course, we all are not perfect. This is why we have the "longsuffering" (Ephesians 4:2) part in our basic Christian love calling
Any of us can be an impossible case, still. This is where we give all to God in prayer, and stay with how we can help each other, and not get isolated with our own little idols of independence while supposing we are trying to help someone. We can find others to share with and help us to help others
"casting all your care upon Him, for He cares for you." (1 Peter 5:3)
We need to be humble to acknowledge how You, God our Father, are the One who truly cares about us . . . better than we can care about our own selves and others.
By the way, if you have a good pastor and maybe if she has, each of you can get what you need by listening to whatever he preaches > trust God to use him
Listen carefully to whatsoever he says, and God is able to apply this
God bless you
Bill