Q.Mango tree dying
Ever since the few consecutive days of raining in San Jose California, the leaves on my mango tree are turning brown, drying out, and now are wilting. It was very healthy before and grew many leaves. I also notice that the stem near the top is a bit wrinkly. Is it too much water? Is it too cold? Not enough sunlight? I’ve brought it in the house now, which is around 70 degrees. Please help.

A Mango Tree can generally survive some heavy rain without issue if the soil is well draining.
If the roots are sitting in wet soil, this could certainly stress or kill the tree.
Also a Mango Tree should not be exposed to temperatures below 40 degrees F. If the tree was wet from rainfall and the temps were cold, this could be a deadly combination. A dry tree will have better chances in cold weather then a wet tree.
You will need to wait and see. You can prune away any dead material and hope the tree will recover.
https://www.gardeningknowhow.com/edible/fruits/mango/growing-mango-trees.htm