Where does it say Charlie is suffering? 
This isn't a right wing/left wing issue. Euthanasia is a symptom of moral failure and certainly not merciful. It's degrades human beings to commodities. 
I'm close to a family whose child has a severe genetic condition, in hospice for a time, and now vent dependent for over a year. She wouldn't survive without assisted breathing. She also is the center of her family, loves them, activity and music. Her life has intrinsic value and not for a government (or you) to decide whether her life is worth living.