Euthanasia should be available for anyone at any age. You don't choose to be born, life has no inherent value, suffering is strictly personal. Suicide is a terrible option with lots of drama, an extremely high failure rate and lifelong treatments or medication that are seen as the solution by society is a conservative convulsion of keeping people alive under any circumstances.
We could set up three sessions with a therapist, to keep people from losing loved ones too fast. But honestly, to me that would feel patronizing. That other people find it important someone stays alive is their problem. If it hurts them too much they can do the same.
There is joy in life and that's beautiful, but on a scale suffering has the possibility to be more intense. Let people die without drama, let them say goodbye if they want with a ceremony, let them choose.
That's the next step in the mentality of a modern civilization. It will fix the drama of wars, hunger and pain as you always have a simple painless solution if the suffering gets too heavy. Just end it, peacefully, whenever you want.