For ill household members

أُعِيذُكَ بِكَلِمَاتِ اللَّهِ التَّامَّةِ مِنْ كُلِّ شَيْطَانٍ وَهَامَّةٍ وَمِنْ كُلِّ عَيْنٍ لَامَّةٍ

"I seek refuge in Allah with His total words from the evil Satan, from every poisonous animal and from the evil eye". (Bukhari)

If any member of Prophet Mohammad (SAW.)'s household fell ill, he used to recite the the four Quls and blow on them.

And recite this dua below seven times for the sick person's good health
أَسْأَلُ اللَّهَ الْعَظِيمَ رَبَّ الْعَرْشِ الْعَظِيمِ أَنْ يَشْفِيَكَ

"I ask Allah who is the Lofty and the Lord of the Mighty Throne that He cures you"

Prophet Mohammad (SAW.) said that by reciting this dua seven times, the ill person will regain his health and if death occurs then that (death) is a different issue (i.e. death is written it cannot be prevented).(Mishkat)