Actually, assisted living is more care/help-oriented as Leila described than training-oriented as Sar2them described. Its a big step above a hospital and nursing home, but is not independent living. We look out for a good friend who moved from independent living to AL last year, so I know the ropes.
I think its a great way to introduce them to living in society while still providing for their needs. Facilities vary, so I hope its one that is well run and will respect their privacy (no leaking info and photos to the paying press by staff or other residents). Once they are stronger and ready, the training can start, either by outside facilitators while they live in AL or in a different setting.
Although Im sorry the younger ones wont be together, it would be a logistical nightmare. I am confident that the foster homes have been carefully chosen to tend to their needs and they will thrive. As others have said, I think its very important for the adult children to have the opportunity to become independent individuals and not be put in a caregiving role with their younger siblings. They need to be able to spread their wings and fly as far and in whatever direction they want.
JMO