With all the Superman/Clark has faced, he probably had never been more scared in his entire life. With this mother and father, he lost them but he didn't see them suffer and struggle like he would see Lois. Such an amazing show!
If someone is suffering and in pain, and the end inevitable, is it not our responsibility to help that person pass as peacefully as possible? People aren't meant to be in constant pain, we're not meant to take that level of suffering. Something...as painful, as HARD as it is...letting go is what we have to do.
Because her husband was literally putting himself through a constant, unending, and excruciating pain not necessarily because he wanted to live on, but because he wasn't able to let go of her and was scared she wouldn't be able to let go of him. So rather than keeping that status quo and forcing themselves to march on that painful, thorny path to get a bit of extra time that won't be spent in peace and acceptance, but worry and pain. So she confided in him that she'll be ok and that it's ok to accept his mortality and prepare to move on rather than clawing tooth and nail for a bit more time that will just be more misery for them both. Pretty morbid, certainly doesn't leave a great taste, but it's ultimately a kindness to let go in some of those cases. I think there's a fine line between wanting to live and being too scared to die and leave the people you love and care for behind, and when it's solely into the latter death becomes more the blessing than the curse.
