How does the SPD person in your family tackle Xmas.
Do they get very hyper or low and how do you all cope with it.

Small family Christmases.

Tuttleturtle I only have my older kids joining us. In all there will be my five kids, one other adult, my sons girl friend, and maybe a baby depending on if he gets moved before Xmas. He is a foster child who is being adopted.
My son sees all these on a Sunday anyway so hoping he won't be too over the top.
Any suggestions for when he gets to hyper would be appreciated.

Our Christmas rule is that we stay home on Christmas Day. On other days, my son can only handle one activity or visit per day. Otherwise, he just can't handle it. My advice is that you know what your child can or cannot normally handle, so don't be overcome by the pressure of the holidays. Set boundaries for your family and stick to it!

Small X-mas gathering of all adults. It's very quiet and not in the least rowdy. But even after 4-5 hours, I get burned out bad enough that we have to go home.

My family also has a rule that we do not travel or go other places for Christmas. We would welcome other family to our home on that day, but we are fortunate that my parents also live close by so any visiting family normally stays with them. I think it really helps to keep celebrations and events like that small. There is so much going on on Christmas morning. All of the presents, smells of food cooking, excitement, etc. I think if we mixed in a lot of other variables it could result in a meltdown.

My son seeks some types of sensory input, but he is also autistic and has trouble in social settings. This can cause him to have meltdowns rather quickly when in a complex sensory and social environment. Sometimes his reactions to things are not predictable, so it is better to control the environment to things that you know from experience they can handle. The last thing I want is for my son to not enjoy Christmas morning, especially if there is something I could have done to prevent any angst.