I'm not a lawyer, but heard that as long as the termination is not because of the sick leave, there's no issue with it. 

Contact a lawyer for a better reply tho. Even an expensive one of CHF 500 / hour will just need a few minutes to answer your question. 

In Geneva there some "Permanence juridique" where you can have some legal advices by a laywer for 30min and it cost around 50-70chf.

http://www.permanence-juridique-geneve.ch/

http://www.odage.ch/fr/permanences

Ciao

The termination period will begin when he returns from sick leave. 

Try Daniel Meyer 022 736 64 36.  He used to give first consultations free on Saturdays - dont know whether he still does this.

How long has he been on medical leave?

Thank you all! We will go to a permanence juridique tomorrow. It is just so odd, the official reason apparently is that there is no need (besoin), while this we never noticed. He is on medical leave for almost 2 months, is the period important? So much looking forward to go back to work...  It is also odd we got the notice only this weekend, but that it has been terminated by 1 September already, I wonder how this is possible. Any other insights remain welcome! 

PS: who is Daniel Meyer? 

Was the letter sent by registered post?  Have you kept the envelopo?

If so, what is the mailing date?

No registered mail, stamp on envelope says 26 September. 

So make a couple of photocopies of the envelope and don’t forget to take it with you when you go to the “Permanence juridique”.

Daniel Meyer is an excellent lawyer.  We saw him at his free Saturday morning consulation a couple of years ago when the Regie was giving us considerable trouble.  He gave us invaluable advice which, with the help of Asloca, meant that we did not lose our flat.

Firstly, the termination will only take effect as from the end of the month, ie Sept 30th.  I would expect that he has 1 or 2 months notice depending upon how long he has been working for XYZ.

Secondly, sounds like the type of company that will not be paying his sick-pay correctly either . . . should normally be 80% of his salary. If he has passed the "periode d'essai" (first 3 months) then there are rules that are outlined in the COO (Codes des Obligations), basically you will be covered by the PdG insurnace (Perte de Gain) that covers you up to 2 years.

Upon leaving a job you can alwways contract this same insurance on a private level but you have to pay the premiums.  You have to make conatct within a month, AND your employer must inform you of this option.

Go see either a lawyer or the prud'homme (more or less free).

Don't give in or give up if you are legitemitly sick.

Good luck.

Thank you all, Glocals community. In the end it appeared all to be a mix of a mess-up of the employer, and our limited knowledge of French. We were send 2 pages, one of which was not intended for us. The other page mentioned an ARRETE and not an ARRET- entirely different situation.

we visited the permanence of the Ordre des Avocats (the second one mentioned by Giuseppe, in the Old Town, the first one said there was currently no one to advice on labour law) and we were adequately helped for Chf 60, only downside is we had to wait for over an hour, but permanence is recommended.

By the way, the avocat also said that Swiss law prohibits dismissal during sick leave. 

If the law has not changed, the employer can only dismiss you after 6 months of sick leave.