Am I able to request a primary care physician to prescribe Minoxidil 15?

I'm sorry for your loss.  I suggest seeing a Doctor who specializes in hair loss to evaluate and go over your condition and provide you information about your best treatment options. There are great non-invasive options like prp/progesterone that work well with Minoxidil. Hair transplantation is an alternative. See an expert. Best, Dr. Emer

You may want to see a hair restoration specialist concerning your hair loss as there may be additional issues other than alopecia related to stress.  As for minoxidil at high doses, a family practice physician may write for it however they must understand that it would be off label dosing.

A primary care provider may not have past experience with minoxidil off label dosing. One can always ask but he or she may not know the questions to ask to make sure it's safe for you to use and may not know the appropriate follow up and monitoring required of someone on minoxidil 15. You may wish to see a physician specializing specifically in hair loss.

Any doctor can prescribe off label doses of minoxidil.  What you need is a good specialist to work with you first before you prescribe a solution to your problem