Well, if this is your preferred meditation to use at the moment of death, it would be quite important to develop it very strongly during your life, especially when you are in moments of fear. When there is the thoughts that you may die, fear may arise. So the capacity to transform the fear into Compassion/Lovingkindness, especially in the ways of the DD meditation, may be very helpful for you. Compassion/Lovingkindness is certainly a good way to die, feeling Compassion for all beings.
I had an interesting dream once which made me change my preferred particular meditation object to another one, perhaps thinking that mine wasn't strong enough. In this dream I was on my veranda and there were spirits, deadly spirits, dragging me off. I started to do Compassion/Lovingkindness to these spirits. But in the back of the mind I thought, "If I do Compassion/Lovingkindness, they won't hurt me." Then in the dream I realized that my Compassion/Lovingkindness wasn't so pure, that I was doing it in order to save myself, so then I started to do Compassion/Lovingkindness more purely, "Ok, they are going to kill me." I started to bring Compassion to them, and to myself. But then I saw fear arise in the dream. So then I thought, "Oh, well, I am going to die," and then in the dream I started to think of the Buddha. A bright pure light arose, the spirits disappeared and everything went peaceful. At that time, it didn't matter to me whether I was going to die or not but what did matter was the power that I found at that time thinking of the Buddha. So now my preferred meditation object at the moment of death is the Buddha.
If you see there is a tendency in you to have Compassion/Lovingkindness so the other person may like you, so the other person may not harm you, then you may need to work on having a much more unselfish wish. That dream taught me the necessity to have a truly unselfish wish, as well as the power of the reflection on the Buddha for me, personally.
Work on letting go of our idea of ourselves, the idea how others relate to me, what they are doing to me, when we do the Compassion/Lovingkindness meditation. Try to make it an unselfish wish, even if that person continues to not like you, to not treat you well. That doesn't mean that you stay around the person if they don't treat you well, but that we can still continue to feel for them and their ignorance. So strengthening the Compassion/Lovingkindness and the unselfishness in our normal life helps us greatly with the Compassion/Lovingkindness in the moment of death.