Well, he can always lodge a complaint with the Spanish government, if he likes. However, "a third party doesn't approve of this, maybe, but can't be bothered to object for themselves" would not generally be taken seriously as an objection to _anything_. Spain's a secular democracy and is under no obligation to defer to what some people think a putative deity thinks.
As popularly depicted, he probably wouldn't be too excited about gay marriage, either, or, if you take Leviticus seriously, mixed fabrics. Should Spain ban those, too?
This is a serious issue which should be carefully considered, but I'm not sure that the religious argument (certainly this rather simplistic case of "some entity might disapprove") should really have any standing.
Ok then, following that same logic I have some assertions.
1000 gods exist, they really do, they told me, you can trust me. For every position your god takes, my 1000 gods take the exact opposite position.
Any rational person would think, "You can't just assert that, you have made an extraordinary claim! The burden of proof is on you to show that your extraordinary claim of personally knowing 1000 gods exists has some basis in reality."
Know that that same logic applies to you and is why you are getting blasted with downvotes.
If it exists and has opinions on assisted suicide, the onus is on it to manifest its will (and prove its existence while it's at it.) In the mean time let's legislate without considering religion.
Regardless, he doesn't matter. An omnipotent being is fully capable of coming to assert his authority anytime he wants. In the absence of that, there's no reason to consider his opinion when constructing laws for actual people to live under.