My father recently past away leaving a fairly complicated Will with properties in Spain, however without any Spanish fluency or understand of their local laws; Mum and I are a little stuck

Now, as far as I know, both of my parents have their names on the deeds... and it's my father whom recently deceased. However I'm unsure if by default, a property is jointly owned, or held in common, which is it?

Also, considering the content of the Will, non of us are beneficiaries
So... who know owns the property? Does my mum still own 50%?? Or does she assume full ownership? And.. how could I possible check (we're in the UK)?

Please could someone advise?

Thanks.