You have had a lucky escape there Varche
As soon as you can put everything in writing to that VW dealer and claim all costs, plus an amount of compensation that reflects the how it has affected you putting all your lives at extreme risk. I would also recommend sending copies of all confirmatory documents from the emergency garage and any pictures you have.
Once allowing a reasonable time for them to reply, as you must state in your letter, if they do not provide an apology and acceptance to pay you the value of the claim, send them a letter of Intent to take legal action.
Now I recognise Spanish Consumer Law may have it differences compared to the UK version of the Consumer Rights Act 2015, so perhaps a consultation with the internet about your laws in this respect, or with the Spanish equivilant of the Citizens Advice Burea, then after that with a solicitor who obviously will charge, but they can add that to your claim for damages