Golly, that is an interesting diagnosis. How did you come to that conclusion?

Thank you for sending the picture. Now my next question is is that not new growth coming out of the top? I am hopeful it is because my immediate answer is that nothing snaps back overnight and IF your diagnosis is correct- and I am not saying it isn't - think about how quickly a person who has been poisoned takes to fully recover. It will take some time and patient watchful waiting. You might try heavy watering to flush salts out from the root zone. You know to be sure you do not have drainage issues. Perhaps filtered sun would also be ess stressful to the plant.

Read more at https://www.daf.qld.gov.au/business-priorities/agriculture/plants/fruit-vegetable/fruit-vegetable-crops/mangoes/faqs-about-mangoes/faqs-pests-diseases-problems

I hope this is helpful information and wish you good luck and many mangoes

Thank you so much for your knowledge. The diagnosis I came to was backed up by the almost daily hypotonic nutrient overdosing my relative did to it and the fact that when I rinsed out the old soil the water came out darker than the most concentrated iced tea you’ve ever tasted. The growth at the too has been “frozen in time” for a few weeks and seems dead to me since the stem below it is black and most likely dead. The only reason it is greenish is because leaves retain pigment for some time after death. I will try to flush out the salt with occasional water; I am just worried about putting it through even more shock. The filtered sun sounds like something I will try for sure. I’m wondering if I should off the top part of the stem which is black to allow new growth from the top? Is humidity also an issue for this plant since it is tropical? Right now some of the dead leaves have fallen off and I have trimmed off some of the dead parts of the leaf that are filled with salt. I am really  worried about the lack of leaves and therefore energy this plant can produce.

Thank you

The clinic is a founding member of the Ohio Plant Diagnostic Network (OPDN), which is a member of the National Plant Diagnostic Network (NPDN). NPDN is a nationwide consortium of diagnostic laboratories that enhances agricultural security by rapidly detecting and monitoring pests and pathogens. The OPDN facilitates the uniting of diagnostics, research, and outreach activities from all over Ohio into one organized and effective communication tool for the betterment of Ohio and the nation.

Having not used this service- I copied it from information sent to me- I cannot tell you exactly how to go about it but you seem so desperate to save the plant and that's my best idea for a true expert to advise.

I generally believe most plants have a strong drive to live and am one who does not give up on plants, will allow them to look ugly for months while they get their act together so I tend to advocate for giving things time. But even assuming the plant is a lost cause, you have little to use by either waiting or cutting the plant back to where it seems to be healthier; that appears to be about 6-8" up from the soil if my sense of size is correct. I do not believe there is a quick fix short of your relative buying you a new plant.

Without seeing it in person, I am truly at a loss and even then I am sorry to say, I really do not have the knowledge to help you. I am so sorry. 

I see... In that case, I will try to access the CWEPPDC at OSU all the meanwhile I will try my best to rehabilitate it. Thank you so much for this crucial information. 

I am truly grateful to you.