He prayed Istikharah more than once about having surgery, and it was not clear to him which option was better; what should he do?

Praise be to Allah.

Firstly:

Praying Istikharah is prescribed when the Muslim is faced with something and does not know what the best and correct option is concerning it. So he should pray and call upon Allah, may He be exalted, asking Him to make what is best easy for him and to avert from him what is not good.

See fatwa no. 11981.

Secondly:

As you have prayed Istikharah more than once and are still hesitant, then what we advise you to do is to carry on consulting people and praying Istikharah in the following manner:

Consult another doctor, other than the one who suggested surgery to you, and repeat the medical examinations and tests that you did, then pray Istikharah and ask Allah, may He be exalted, for guidance after that, because consultation (of people) should come before Istikharah.

Or change hospitals or the medical team that was allocated to you the first time.

Then after that, resolve either to go ahead with the surgery or not to do so, and if you find one of the two options becomes easy for you and you feel at ease about it, then that is what Allah has chosen for you.

Shaykh al-Islam Ibn Taymiyah (may Allah have mercy on him) said: If a person prays Istikharah, asking Allah to guide him, then whatever his heart is opened to and he feels at ease with, and is made easy for him, is what Allah has chosen for him.

End quote from Majmoo‘ al-Fatawa (10/539).

If you are still hesitant, then there is nothing wrong with praying Istikharah repeatedly, until it becomes clear to you which of the two options is right.

Badr ad-Deen al-‘Ayni al-Hanafi said in ‘Umdat al-Qaari Sharh Saheeh al-Bukhaari (7/225):

If you say: Can a person pray Istikharah repeatedly concerning a single matter, if it is not clear to him what the right option is, whether to do a thing or refrain from it, so long as his heart is not open to what he should do?

I say: Yes indeed; it is mustahabb to repeatedly pray and offer supplication (du‘aa’) concerning that. End quote.

In al-Mawsoo‘ah al-Fiqhiyyah al-Kuwaitiyyah (3/246) it says: From the views of the fuqaha’ it may be understood that Istikharah may be done repeatedly when the matter is not clear to the one who is seeking guidance by means of praying Istikharah. End quote.

We ask Allah, may He be exalted, to make your affairs easy for you.

And Allah knows best.