The question I shall be looking at is the modern meaning of euthanasia instead of the original Greek meaning "good or pleasant death" (ref). Nowadays, euthanasia has come to mean "the painless killing of men and women to end their sufferings", and it is often referred to as mercy killing (ref). Euthanasia has classified into five main categories and in Hastening Death article, the authors clearly listed out all the types, including active or passive and voluntary, involuntary or nonvoluntary. And in Liang's case, I will put it under the active nonvoluntary euthanasia umbrella. It was because Liang is the son, someone other than the dying individual, who committed an act, electrocuted his mother, Ms Zhang, with the intention of ending that individual's life, that is active killing of his mother with intention. Euthanasia performed actively when Liang's mother, the individual who was unable to consent, was in a comatose state after her stroke, that is "mercy killing" was performed nonvoluntarily (ref). Non-voluntary implies that there is no vulantariness in the sense that the patient is not capable of either denying or giving consent (as in the case of the permanently comatose or brain-injured patient) (ref). This was exactly what has happened for Liang's mother, her son killed her when she was comatose. Whatever active or passive; voluntary, involuntary or nonvoluntary; assisted or not assisted suicide, I do not buy the term euthanasia or simply saying, I do not agree with "mercy killing". .
Now, comes to Liang's case that took place in Mainland China. Clearly, Liang deliberately killed his mother, a comatose stroke patient without say to her death. Although the court did not query Liang intention, as mentions in the article, "the Minxing District Court never doubted Liang loved his mother or believed that he was acting out of malice.", Liang was sentenced to 5 years imprisonment (ref).