In love with Childhood bestfriend - but parents are against it

[Unregistered]

hi,
me and my bf are 24 years been best friend since childhood. but we realized we are in love since 4 years. his parents are ok wth it but my parents are refusing because he is a christian and i am a brahmin.
my father is a very anxious person with medical problems. i have a younger sis. initially they agreed that i can stay single but not marry him but now they want me to get married coz only then my sis can get married.
i dont want to hurt my parents but cant think of marrying some one else.
kindly help