In this situation, please make a will. You don’t necessarily need a lawyer*, you can write one yourself.
Now I have no idea how to go about getting your son on the Family register - I’ll leave that to others. But don’t forgo writing a will while you pursue that.
I stress this because without a will your estate falls under statutory inheritance. As such, your spouse gets 50% of the estate, your children split 50% amongst themselves. The danger here is if the Powers That Be decide your child who is not in the Swiss Family Register is not your child for inheritance purposes. I don’t know if they can do that - hopefully someone else does - but I would want to take all steps to ensure that your child couldn’t be left out in the cold. Why take that chance?
If you want your non-Swiss child to be guaranteed an inheritance, your choices are to either try to get your son properly acknowledge in the Family register or to make a will. Or do both.
Making a will takes minutes, and doesn’t have to cost you anything. I would strongly suggest that you take those few minutes and write your will to include your non-Swiss son. With a will you must leave 25% to your spouse, 25% to your children, and then may leave the remaining 50% as you choose. Then, if you are not able to get your non-registered son on the family register, you could leave him his share of the estate from the 50% Frei Quote. An equitable work-around.
(There might be tax consequences to the ‘non-child’ child, but that needs to be discussed with a tax pro.)
You can find examples of a Swiss will online to use as a template. Red Cross, Pro Senectute, most banks have published these. Your will needs to be (with a few exceptions) handwritten. Also, make sure that your family know where your will is kept. FYI, some Gemeinden might offer a service where they hold the will, perhaps for a small fee.
You can also find inheritance calculators online to help you understand what happens with and without a will.
You can, and should, also continue pursuing getting your son in the family register.
But I’d still write a will, just in case something were to happen while you are tilting at the windmills of Swiss bureaucracy.
- If you anticipate even the slightest whisper of conflict in the distribution of your estate, please see a lawyer. A lawyer isn’t all that expensive, and could save endless heartache. The peace of mind that your wishes will be followed is well worth the cost, IMO.