Hadithcore
Al-Adab Al-Mufrad, 527
da’if· Al-Albani

Nafi' reported that when Ibn 'Umar visited someone who was ill, he would ask him how he was. When he left him, he would say, "May Allah choose what is best for you." He did not say more than that.

حَدَّثَنَا أَحْمَدُ بْنُ عِيسَى، قَالَ‏:‏ حَدَّثَنَا عَبْدُ اللهِ بْنُ وَهْبٍ، عَنْ حَرْمَلَةَ، عَنْ مُحَمَّدِ بْنِ عَلِيٍّ الْقُرَشِيِّ، عَنْ نَافِعٍ قَالَ‏:‏ كَانَ ابْنُ عُمَرَ إِذَا دَخَلَ عَلَى مَرِيضٍ يَسْأَلُهُ‏:‏ كَيْفَ هُوَ‏؟‏ فَإِذَا قَامَ مِنْ عِنْدِهِ قَالَ‏:‏ خَارَ اللَّهُ لَكَ، وَلَمْ يَزِدْهُ عَلَيْهِ‏.‏

References2 variants
In-Book Reference
Book 29, Hadith 37
English Reference
Book 29, Hadith 527