I want to prepare for my new preschooler with Down syndrome. What things should I do to prepare for their arrival? What things should I have ready for him to sleep, play, learn with? What are some unique things that I might consider getting for him?
One place to check in with when preparing for the adoption of a preschooler with Down syndrome would be your local school system to get whatever possible started for him (possibly just to inform them that he will be coming in to the system soon and find out what options may be available for him).
Your pediatrician is also a necessary place to start because they will likely be the first person that the child needs to see once coming home. Letting them know that your intention is to adopt this child is a good start, but if you don't already have any children with Ds they may also be a source of information or a person you may want to give information TO! :) There are special weight and height charts for children with Ds and it's important that your doctors use these to follow your child's growth appropriately (if they do not fall on the typical scale... which some will and that is ok too!)
If you don't already have contact with a cardiologist this is another thing to do before coming home. Even if your child's paperwork says there is no heart issue, you will probably want to have them checked once thoroughly simply because they have Down syndrome. Half of the children with Ds have a heart condition and a lot of those are 'simple' yet many are more complex. There will likely be 'sounds' that are audible to a physician if the child has a heart defect, but some conditions such as a PDA or PFO may not have an audible sound but can be seen on an echo. Let your cardiologist know what the expectation of cardiac diagnosis is and especially if there is a firm diagnosis, discuss what that means for your child. Especially older children (over 3), who can have underlying lung and cardiac issues if they have a large defect that has been left unrepaired.
If your child is able to pull to a stand and is a preschooler then I would guess that for sleeping he will probably be ready at least for a toddler bed. If you'd rather not go that route then a twin bed should also be fine- with a side rail. If the child is small and you can babyproof the room with a gate at the door, maybe consider a mattress on the floor for a time until it's safe to have him sleep at the height of a twin bed.
For play, a kid is a kid :) If the child is significantly developmentally delayed you may find that your child interacts with toys that are aimed at a much younger age group. In an orphanage sometimes there is an abundance of toys but often there is not much available. This completely depends on where they've grown up! Many children find musical toys and cause-and-effect toys the best to start with. Toys that teach are great, especially if they speak things that you will want your child to learn such as colors, body parts, alphabet, and numbers-- in English! :)
In our home we found that toys that are "all in one piece" tend to be played with. Toys with multiple pieces tend more towards throwing and are brought out more when the kids are being helped with them :). Puzzles, shape sorters, play dough, and alphabet magnets are all great but for us they are stored away and come out during instructional playtime! Some other things like this are 'pegs' and a foam pegboard, pop-beads (an infant toy but good for hand-eye and strength development), and a large bin of rice or beans for sensory play. Lacing/buttoning dolls, magna-doodle (with attached pen), Leap Frog toys that are one piece (the alphabet bus is a favorite though the 'dolls' aren't often with it), the learn and play puppy or another similar toy that says body parts and nursery rhymes, musical piano toys and other musical instruments... these type of toys are great for individual playtime and 'teach' while a child plays-- and aren't in 100 different places around the house :).
Some unique things you might consider that are definitely NOT NECESSITIES but might be something you find useful based on your situation...
A bar that goes in the door frame made for holding a swing is a great thing to use during long winters or hot summers if outdoors are not accessible. These can hold up to a teen's weight and can be used with any swingset swing such as an infant/toddler seat or a regular preschool swing. The cost is higher, but it's something you may find you get a lot of use out of- swinging can be very therapeutic!
A sandbox is another great tool if there's a dry place outside to have one. Especially kids that need a lot of sensory input, such as those that have not had a lot of interaction and are really seeking input. In a similar way, playtime in the tub provides stimulation all around in a fun environment but it is a different type, so both are great tools!
If your child is standing, then a small trampoline with a 'bar' to hold on to and jump is great fun, good exercise, and a wonderful therapy tool as well!
I'm adding this in later... a ball pit is also a lot of fun! Colorful balls can be purchased about $10 for 100 balls and a $5 baby pool will hold 100 or 200 balls easily. It's not an expensive toy, but it will probably get a lot of use. The only hard part is keeping the balls contained :) Garbage bags, a bin, or the bag the balls came in work fine for clean up but we have tended toward leaving that activity out- at least for now- and just putting up with the balls (and putting them away constantly!) since the kids play with it so much!
I hope others will add their own ideas and thoughts to the comments. There's SO MUCH out there that these are just a few of many and are definitely not necessities... simply suggestions!!