Related To Contempt Of Court

I am plaintiff in a civil case which I have brought against my family members in a property dispute. The defendants are my brothers and sisters. After 1 and half year in the case, one brother and one sister have expired. My questions are as follows: 1) is it my responsibility to inform the court that they have died. 2) I don't have access to their death certificate. One has died in India, and other died in USA. I never got along with them. DO I have to make changes in my plaint, even though I do not have proof of their death. 3) What happens if I do not let the court know that the defendants are dead. 4) The defendants have their own lawyer and he has not informed the court even after 3 months have passed. Is it my (Plaintiff's) responsibility or their lawyer's (defendants) responsibility to let the court know that 2 out of 4 defendants are dead. 5) If I do not let the court know because I can not get their death certificate, what is the legal remedy to let the court be informed about their death. 6)Do they get removed as defendants if their heirs aren't interested in joining the civil case. Kindly let me know the appropriate legal opinion. Thanks.