Indeed. Hubby has two full 10 year passports one of which expires in June this year and the other in 2019. He won't bother renewing the expiring one as he doesn't really need two anymore.
You would need to clarify that before he leaves. I'm not sure it's possible to process a citizenship application for somebody who is residing abroad and he won't have enough time to complete the process before he goes to uni if he is planning on going this year.
He can put his C permit on hold during his studies abroad for up to 4 years but I'm not sure how that would affect the residency status for naturalisation. It's certainly worth checking beforehand.
An issue with naturalizing that hasn't been mentioned on this thread - but has on many others - is that as a Swiss citizen your estate will be treated under Swiss inheritance law, claiming Heimatrecht would no longer be an option for you. (Assuming you kick the bucket while resident in Switzerland.)
He won't be resident, if the resident permit is on hold............ This is to prevent people 'gaming' the system, no doubt wanting to go to a University outside Switzerland would be viewed as an odd decision by a 'true Swiss'
When you apply for the ESTA, I'm pretty sure they ask you if you have dual citizenship. They probably also now ask you if you have been to Iran, Syria etc..... lie and you are asking for trouble!
And, if being really honest, get it before leaving.
If you are not resident in CH, you do not need to pay tax here. Just like you do not pay tax in the UK as you are resident here. He would simply hold UK and CH passports. Where he is a registered resident is another matter.
It was a good 6 months ago since I did my last ESTA application and I'm pretty sure they only asked if I'd ever entered the USA under a different passport / name..... but I wouldn't lie... having lived in the US for 2 years I know what a PIA immigration officers are....
If it came to choosing between travel elsewhere and the USA I just wouldn't go back. I've been to most of the major cities and 23 states now I only go back to go to NYC if hubby is there longer than a week....
I edited my original post to make the meaning clearer. I meant the residency qualifications for naturalisation purposes if he were to leave and come back again.
Would it mean starting from zero again? I seem to recall a thread here asking this very question a while back but I don't recall what the answer was.
Auslandschweizer-Organisation says this about paying a military service exemption tax:
"Military service exemption tax
Every citizen liable for military service who fails to meet his military obligations fully or in part either by completing military service or in the form of a civil service, must pay compensation called the exemption from obligation to serve tax. This obligation is valid both for Switzerland and abroad. Since June 1, 1974, however, Swiss expatriates only have to pay the exemption tax for the first three years of an uninterrupted stay in a foreign country. If he has spent years abroad beforehand they will be added to this three year period. From then on they are released from this obligation. This means that, as a rule, Swiss citizens born abroad and liable for military obligations do not pay the exemption tax.
If dual nationals have their residence in their second country of origin they are not required to pay the exemption tax if, during the year in question, they have done their military service or completed a form of civil service, if they have already paid a tax or if they have already completed their ordinary service in the army of their second country of origin and remain at this army's disposal."
If I understand it correctly the son will be considered resident at his oarent's house during his studies abroad as long as he is not away for more than six months at a time.
The federal government's nationality manual states that in cases where children of Swiss residents leave Switzerland to pursue studies in other countries, they are considered as remaining resident in Switzerland as their centre of interests is in Switzerland, so long as they remain registered in a Swiss commune.
Cantons may not be fully aware of the legal implications and therefore one might have to remind them. The only big issue I could imagine would be a commune arguing that since the applicant spends considerable amounts of time outside Switzerland, he or she is therefore not sufficiently integrated.