Hello, my name is ***** ***** I am a qualified lawyer happy to help you this evening.
The dealer's stance is very surprising in my view. The dealer had sole control of the vehicle whilst at their premises and they take all responsibility for it too at that point - it is not your Son's fault that the vehicle has now been written off. If Nissan tried to sue, I cannot see the court saying for one minute that your Son should pay for the repairs for a vehicle which has been written off during the dealer's custody of the vehicle. It would be wholly unreasonable to expect your Son to do this - I can only think that someone with no legal knowledge has told your Son this with a complete disregard to his consumer rights.
The arson attack is an intervening issue which has made the return of the vehicle no longer possible. The dealer will have insurance for this so they need to bear the cost of all of their losses and not try to pass on this loss to their customer (your Son).
My advice is to defend any claim they might make for the repairs - if they choose to sue then the court will send a claim form to your Son which sets out the claim from the dealer - and a response pack for your Son to fill in. It is vital he fills in the response pack to confirm he wants to defend the claim - then return it to the court. So that you know what it looks like I have attached a copy (just for reference). I can help with filling out the defence form if required - just come back here or post a new question and ask for me.
In the meantime I recommend speaking to Trading Standards about this. Their site is here with their contact details :
I would not recommend your Son pays them anything for the repairs for the above reasons.
I hope this answers your question – if so could you please click 5 stars at the top of your screen, that will give me a rating on the site and I can answer any follow up questions at no extra charge.