Would you marry a person who you hardly know or would you marry a person who has some sort of an ailment that would ultimately result in his/her death..???
But wouldnt it sadden your parents to know that you will me marryin an individual who will not be with you for long???...after all that they have done for you..is this how you d like them to feel??
its not a question of morality but rather its a question of love. and if you really love that person, these things wont be much of a hindrance for the two of you to get together.