There are some special duas for ill persons, dua for grief and sorrow, and different occasions.
Allah Almighty says in the Quran:
“When my servants ask you concerning me, (tell them) I am indeed close (to them). I listen to the prayer of every suppliant when he calls on me.”[2:186]
Prophet Muhammad (PBUH) said,
“Nothing is more honorable to Allah the Highest than dua.” [Sahih al-Jami` no.5268].
He also said:
“The most excellent worship is dua.”[Sahih Al-Jami` no. 1133];
Dua for an ill person:
أَسْـأَلُ اللهَ العَـظيـم، رَبَّ العَـرْشِ العَـظيـم أَنْ يَشْفِيَكَ
Meaning: I ask Almighty Allah, Lord of the Magnificent Throne, to make you well. (Recite seven times in Arabic)
Dua When Faced with Grief or Sorrow
يَا حَيُّ يَا قَيُّوْمُ بِرَحْمَتِكَ أَسْتَغِيْث
“O Living One, O Self-existent One, by Your Mercy I seek help.”
(Tirmidhi)
Dua When Visiting the Ill
لا بأْسَ طَهـورٌ إِنْ شـاءَ الله
No need to worry. It (this illness) is a means of cleansing from sins if Allâh wills.
(Bukhari)
Dua on Laylatul Qadr:
Aaisha (R.A) reports: “I said: ‘O Messenger of Allah (PBUH), should I find myself the “Laylatul Qadr”, what shall I pray.
The Prophet (Pbuh) replied: say,
عَنّيْفَاعْفُالعَفْوَتُحِبُّعَفُوٌّإِنَّكَأَللّهُمَّ
‘Oh Allah, indeed You are most forgiving, You love to forgive, so forgive me.’
[a-Tirmidhi]