Firstly my sympathies for your situation, it can't be easy.
I see three options, none of which are really ideal.
a) You cancel and pay the early disconnection charge, which won’t be small as you still have some 22 months left on your contract.
b) You manage to transfer your existing account to your parent’s property. Now having two separate accounts at one address is not unknown but is really quite unusual. It will require an (additional) physical connection to be made from the VM street cabinet to the house, a second omnibus to be fitted, a separate hole to be drilled through the wall and a second hub to be installed - even if you never, ever use it! In addition you might find it ‘difficult’ to get VM’s customer service staff to agree to arrange the installation! There is a non-zero chance that they will assume that you are taking over the property and terminate your parent’s existing contract!
or, and this might be controversial;
c) You do nothing! You continues to pay for an internet connection to a property you no longer live at, VM won’t care! If, if you are sure that you will be moving in six months or so, only then do you transfer the account to the new property. On paper, this might just turn out to be the cheaper option. However what will mess this up is if the new owners of your existing property also want VM services. If they sign up or want to transfer an existing service, it’ll become very messy, very quickly for both parties!
Option a) will cause you the minimum of fuss (which you could probably do with) but the maximum cost. B) is possible assuming that VM will play ball and your parents are OK with extra holes drilled in their house! Option c) is, on paper, the best but does require a number of things to align which you have no control over. Should the new owners want a VM service, it throws a massive spanner into the works