Firstly you are not mean at all to be having major reservations about this.
Only your family will know what's right for your family. We are all different with different tolerances and preferences. You could have seriously outgoing kids who will benefit from having slightly older fun Aussies to stay, or you could have quiet kids who need downtime at home after a full day at school. There really is only your right answer, and it's helpful that you're getting lots of perspectives here to help you think through all sides of this.
I have experience of young travellers staying in our house when my eldest was heading near to exam years, and will share that below. But firstly few things jump out at me - I note that this conversation seems to have happened from bloke to bloke??? Your husband and his friend? Echoing some of the earlier comments, unless your family is unusual, and with the best will in the world, so much of the emotional workload of the household does end up on women. Even if you're lucky enough that you have a fairer balance in your household you both need to sit down and literally write down the list of things that will be added to each of your workloads and decide if that's ok. But in general a bloke to bloke conversation might just miss out some of the aspects of what this visit would mean. If you do go ahead with this could you have a Zoom call with both parents to get their individual perspectives of them. One of my Aussie cousin's daughters came to stay with me for a week a couple of years ago and even for such a short visit, my cousin spelt out for me before hand how messy she thought her daughter was and wanted me warned about setting rules about cups in the sink and clothes on the bathroom floor
it was great to get that honestly ahead of time. She literally wrote it for me on a numbered list on What's app!
Secondly, travel is meant to be something you do to grow up and be self sufficient - in my opinion that should really include earning the money to travel. My eldest worked her socks off for 9 months in order to be able to travel and only stayed with family in Australia and New Zealand for 2 weeks maximum until she got settled in each country. The rest of the time she slummed in hostels! Or did work aways. So I'd want to know that anyone coming to stay is also coming travelling with that self sufficiency mentality. Not 'Daddy has organised free things for us' mentality. For example it would be much simpler for you, and much much much more appropriate for their self development that you only cook for them now and again, and they supply their own food - maybe out of generosity you could say that pasta and bread will be in unlimited supply but everything else is on them. It's not about being kind - it's about your workload, and frankly their own development.
Thirdly do you use your spare room for your own friends and relatives? Are you going to have 6 months where no one else can stay? Do you want to reserve the right to let them know you need the room - that it's not their whole 6 month dumping ground. And if that clashes with time they want to be in the UK they could travel somewhere else in the UK, or they can stay in a hostel -that's what most young travellers do.
Having had all those reservations for you, and groaning for you when I first read this message, we did have youngsters staying in our house a few times - the longest for 6 months. And as others have said the ultimate upside for our children, particularly the eldest who was in mid-secondary school years, was wonderful. The usual teenage hullabaloo at school - the exam talk, the friendship issues...were all put into perspective by these lovely youngsters who were out the other side of all that and let her see that life could be fun. She would come home from school and download on these girls and be so much happier than if she'd talked to her boring old mother! In her 20s now she's still in touch with them in their early 30s. Only recently we had two Autralian 25 year old lads staying for only one week, and our youngest who is now late teens loved chatting to them late at night, and was really buzzing about the things they were telling him about life, travel, university, making decisions about your future. So there is that possibility of some lovely new young people in your kids lives, who they might even travel to see in years to come. With the caveat that you don't know these two very well of course.
Finally, my one major recommendation if you do go ahead is to set some really firm rules about it all. This isn't about having house guests for 3 nights where you do everything to make them feel at home and generously provide everything. This a very different transaction if it does go ahead. So be really clear - spell it out that it could go wrong (that has to be obvious to anyone - whether they're 18 or not) and what do we do to prevent that. From the 'big' issues of them coming home late at night loud and steaming drunk, to the small issues of when the washing machine can be used. (For example I bought a cheap spare clothes horse for the youngsters who stayed with us and they kept it on the landing near their bedroom at night, and put it in their room during the day when they were out).
Good luck! There really are pros and cons, but only your family knows what's right for your family (ps your kids are old enough to be part of this decision too - it's not your husbands alone - I'm slightly worried that he hasn't involved them before all but saying yes). It might not work - and your husband and his friend need to agree what it will mean for them if it doesn't work. So that their friendship doesn't end up being part of the equation.
it was great to get that honestly ahead of time. She literally wrote it for me on a numbered list on What's app!
