Anael ... As QNSue already mentioned, it does take a special person to work with special people! Bless you for being so considerate as to share your time and work with these people. My Mother had alzheimers, and I know all too well, how sad and somewhat pathetic they become. I learned you had to let it flow and go, and enter into their world. There was no sense fighting her and her reality and upsetting her further, rather better to join it, as best I could. I knew it was no longer her, rather what we were left with because of the alzheimers. Similarly for the mentally challenged, dependent on their functioning level. Though, I was taught by a Director of one of their schools, that they were more like us than not! And to not be drawn into thinking they were different. hhmmm? big lesson learned and it has stuck with me for years.
The laundering issue, should not be an issue ... IF ... you abuse your fabric becore you start sewing. Wash in as hot of water as possible then likewise hot dryer. Then use a polyester batting with machine quilting.
The PC would be a wonderful gesture, though the amount of work you put into each block, may not be appreciated. ITA larger bolder pieces may be better, to give them a larger piece of fabric to see and enjoy. Or what about using your PC blocks, and spacing them with larger pieces of fabric?? That way there's some detailed piecework in there, along with bigger blocks. My oh my, the 95 PC blocks, might become a whole set of quilts!! Now wouldn't that be something to see each afternoon when they have their naps?
Too, I'm sure their caregivers would appreciate the cheerfulness your quilts could bring each afternoon instead of drab brown institutional blankets! As well as their family members feeling more at ease with the care and concern they are receiving while at the day centre.
Good Idea ... share your idea with the Centre Manager and find out what requirements there'd be for you to make and donate these.