How to secure a better future for a severely disabled adult in Bulgaria?

My regular readers may remember that I had a post asking for information about S., a disabled girl institutionalized after her birth 17 years ago. The information was sought by a lady who had adopted this S.'s twin sister. Recently, this lady informed me that a regional child protection agency had finally found S. She is at an institution for mentally retarded children aged 3-18 in a village in North-East Bulgaria. (For privacy reasons, I prefer not to give here the girl's full name and the institution in question.)
At some point after turning 18, S. will be transfered to an institution for disabled adults. The adoptive mother of S.'s sister is concerned about how this move could be suited to S.'s best interest. She wrote, "We are committed to helping this girl and we are now exploring what our alternatives are. Since S. will be 18 in July we need to act fast to make sure that she is moved to an institution that will afford her better care. I welcome any suggestions any of you may have. Many thanks!"
After the BBC exposed the shocking conditions in Bulgarian institutions for abandoned disabled children and our European partners began to exercise much needed pressure, options for the disabled Bulgarians seem to be slowly improving. But does anybody know how to find the best option for S.? She is not a mildly disabled person who needs only material support and accommodations. S. has severe mental retardation and motor impairments. She is non-verbal and has no self-care skills. She has some ability to move by a wheelchair, but spends most of her time in bed.
If you have in mind something that may be useful, please don't hesitate to share it.