is this the leave for MOB station or the go to war ceremony? If its leave for MOB station -it varies by unit but in the state my husband drills in we have soldier readiness processing the two days before. The night before the VFW hosts a dinner for the departing soldiers and their families-usually casual dress and very relaxed. We are from a small state population wise and large area wise and people are spread out so the VFW folks do this to give us a little extra time together. Day of the ceremony its self the Govenor comes and speaks as well as the Adjutent General and the unit Commander. If the unit is actually leaving that day-they get on the bus or the plane and go-if they are in an element that leaves later-( depends on the size of the unit-a Brigade combat team is 3500 plus soldiers and they dont all travel the same day) you just go home and drop him off the day they leave.
If its go to War-thats done at the MOB site at the end of the 4 day pass. Thats a pretty big deal. At Ft Carson and Ft Hood the post or Corps commander speaks, the Post or Corp Chaplain speaks and leads a prayer, the Unit does a pass in review and sometimes "cases" their colors. Then they say goodbye to the families and are put on lock down til they fly.
As for dress-go with what you are comfortable in-the leave for MOB station the time i went was on a day that was 20 below-and we said goodbye outdoors so we wore jeans and sweaters. The other times Mike has gone ADVON and left a month before the unit to set up -dropped him at the AFB and kissed him goodbye-watched the plane take off and came home-skipped the ceremony which was later. The go to war-once was also in winter and held in the Special events center at ft carson which is not heated-so again jeans and sweater. The other times were on the air field at north Ft hood..no shade in summer-shorts, t-shirt, hat, sunscreen and lots of water.
Take lots of Kleenex and if you wear contacts-wear your glasses-you will cry-alot. Hang in there-we all make it thru this -and if you need to vent-or someone who has been there and done that-more than once -to talk to -send me a pm and i give you some contact info.