One of the things to consider before moving, is how easy (or what it would cost) to reverse the decision. Don't burn your bridges in the old place.

If it is permissible to take children out of school, while still living where you are now, would it be possible for you to come, with one or some of the children, for 3 months? Could you visit, and stay with friends or in temporary accommodation, while you go on fact-finding missions to the school authorities, and the tax office, and the support groups your son may need, and work out the budgets, etc.? Depending upon the exact ages of the children you bring along, you could do some sort of home-schooling so that, if they're going back into the Aus school system, they won't be too behind.

Make a list of your OH's 5 main concerns, and specifically investigate these.

You guys all make such good points and its so helpful to have all your kind and thoughtful comments that help to solidify what I think I am already realising but just don't want to have to do...thanks for taking the time to weigh in...its helpful to hear other perspectives to balance my own (obviously) biased view.

I'm not afraid of the stress of re-entry myself because I thrive on stressful situations and am usually at my best when things are a bit crazy (I have very high energy levels and love a challenge!- I think that's how I survive with 4 kids and all the moves we've done - I was brought up as an expat kid and moved A LOT as a kid/teenager, so am used to it) But I do need to be more considerate of the kids and the anxiety it will bring and the extra stress for my husband for sure and wait till he's really ready himself, rather than me pushing him.

I think I do need to let go of the dream to come back to Switzerland for now though and just put it all on hold, while we sort out the here and now with kids needs etc...its tough...I guess I just need to embrace the uncertain and the not knowing how things will pan out.

I like the suggestion to come back for a holiday at some point, or fact finding mission before making any decision. We hadn't considered this because of the cost to come as a whole family at some point, but I just mentioned the idea to my parents who live in NZ and they have said they would love to come over to Aus and look after the kids for a few weeks so my husband and I could fly to Switzerland and do that at some point...although not till coronavirus is over or I told them we risk not getting back and they would be stuck with the kids! hahahah!!

The last time I was in Switzerland was 7 years ago, but my husband has been back 3 times during that time - once for work and twice to attend his grandfather's then grandmother's funerals. It was too difficult for me to go with him at that point because of our young kids, so while he has felt connected with Switzerland, I've very much missed it the most. But I guess that's ok to miss it. Doesn't mean I have to jump there asap I guess ;-)

I think I'm just grieving a bit for the ideal place in my mind that I need to give up...I loved living there so much before we moved away to get help from family in NZ back when I was having our 4th child - I had a very difficult pregnancy and knew we needed to leave so I could have extended help for a long recovery - but hadn't wanted to leave permanently, although we ended up having to in order to make it work in NZ.

And I thought I was finally at a stage now where we could survive back in Switzerland again on our own now that the kids are older and much easier (or so I thought!) ...but finding out about my son really shows me that it wouldn't be a piece of cake either and it highlights the difficulties we would face on re-entry with extra stress from integrating back into french and schooling etc. and the added stress of having access all the ASD/ADHD support in french at this point for him...

So having to change course because of the ASD issues is hard...but I have been encouraged by all your posts to look on the positive side of things and that a change in course doesn't mean thing will be bad...might just be a long delay, and who knows how many other enriching experiences we will encounter here instead in the meantime. Life always throws surprises at us, I guess it just how we choose to respond to them that makes it awesome or not (talking to myself...)