I do think that if there comes a time in your life where you are simply a burden to your family and friends. When you require 24-hour care and have to suffer the indignities of not even being able to do the basic things in life like eating, washing, and going to the bathroom on your own; not to mention being a financial burden draining the family resources then I don't think it would be a dishonorable and cowardly thing to prefer death.
Of course, Luke was nowhere near this state and though I can't put myself in his place it seems hard to justify him taking his own life.
The thing to ask though, is do they see it that way? My dad was ill and thought he was a burden to us. This man gave me life. Changed my diapers. Clothed me, sheltered me, fed me and loved me. Taught me how to be independent. He did EVERYTHING for me.
And then when his life got rough he just assumed he was a burden to me and my siblings and hid his health issues from us.
This bothered me to no end because I would have no problem taking him on. No issues, feeding, bathing, cleaning him, etc. He did it to me for 20 years. It is the least I can do for him.
I realize not everyone feels the way I do but often people ARE NOT burdens to others. They just think they are.