Place a family photo in baby's cot, or just one of the brother or sister. Leave messages on the cot for the sibling from baby i.e. They could check to make sure that you wash your hands, and help to inform staff if soap or paper near the sinks and basins have run out. Keep some story books, paper, pencils etc by baby's cot for the sibling. Decorate a box to keep them in.
Kids enjoy being involved in planning.
Negotiate a time for their visit, i.e. 10, or 20 minutes and tell them what will happen when their time is up. Sit in a rocking chair with sibling on your lap and read a story. Celebrate their achievement by telling family and staff. When you come in with your partner, or another adult, take turns with baby and sibling, i.e. while one is having a cuddle with baby, the other is reading or playing quietly with your older child. Using a diagram of the medical equipment supporting your baby, talk with the sibling about the names of the equipment and its purpose.