Having second child while husband has cancer
23-5-2016 | IslamWeb
Question:
My husband is suffering from brain cancer. We have one son and want a second child, but we do not know about the consequences of my husbands disease. We are already listening to ruqyah (healing through the Quran and supplications), but we are not sure about his life. In this case, we are concentrating on our first child. Does the sharia allow us to have a second child?
Answer:
All perfect praise be to Allaah, The Lord of the worlds. I testify that there is none worthy of worship except Allaah and that Muhammad, sallallaahu ʻalayhi wa sallam, is His slave and Messenger.
Firstly, we implore Allaah to bless your husband with a perfect recovery that leaves behind no illness.
You should know that it is allowable for you to have a second child, or even better for you to do so. The Islamic sharee'ah encourages reproduction and having many children. The Prophet, sallallaahu ʻalayhi wa sallam, said, “Marry the one who is fertile and loving, for I will boast of your great numbers on the Day of Resurrection.” [Abu Daawood and At-Tirmithi and Al-Haakim who graded it saheeh (sound), and Ath-Thahabi and Al-Albaani concurred]
ʻAa'ishah 
reported that the Prophet, sallallaahu ʻalayhi wa sallam, said, “Marriage is part of my Sunnah, and whoever does not follow my Sunnah has nothing to do with me. Get married, for I will boast of your great numbers before the nations.” [Ibn Maajah- Al-Albaani graded it hasan (good)]
You should also strive in utilizing all the available means to seek a cure for your husband and consult the doctors and specialists. You should also recite ruqyah, give him Zamzam water to drink, and do other similar things (that might help him get better). You should also supplicate Allaah frequently and never lose hope. Cancer does not necessarily end in death, nor is it incurable, as some people assume. Jaabir 
reported that the Prophet, sallallaahu ʻalayhi wa sallam, said, “There is a remedy for every illness, and when the remedy is applied to the illness, it is cured by the permission of Allaah, the Exalted.” [Muslim]
Moreover, Thawbaan reported that the Prophet, sallallaahu ʻalayhi wa sallam, said, “Nothing repels the divine decree except supplication, and nothing increases the life-span except righteousness and dutifulness.” [Ahmad and Ibn Maajah]
Allaah knows best.