Oh my goodness - you've got a lot on your plate at the moment, haven't you - I'm sorry.
Obviously, you need to be able to go away with a clear mind, in order to be supportive of your partner.
I wonder if it might be possible for 'your couple' to be able to look after little Jake for one night before Sunday? Then at least Jake will know that 'mummy's coming back'!
I'm really not sure of the rabies rules - but the UK's rabies free. I realise it's a bit late to organise a pet-passport (is it?) but there are some wonderful people that could look after Jake nearer to either Heathrow or Gatwick here - so at least you could visit him, should you ever have to come here again!
I truly wish you luck - hope it all sorts itself out - and best wishes to your partner