I think, from memory, there have been several court cases, where partners who have assisted their loved one to die have been dealt with very leniently - whatever the judicial stance is lawfully.
I'm not saying its right or wrong, but it certainly needs reviewing.
If someone of a sound mind, who has the misfortune to have a terminal illness, decides that they want to end their suffering - so long as their family agree, and I suppose his/her GP - then why not?
No one's been murdered.
After all we can choose to end an unborn babies life within so many weeks of conception without quibble - the unborn child has no say in it!