Do not add fabric softener or bleach even on a white tie.
Can you put a silk tie in the washing machine. The all-natural softener goes into the fabric softener compartment. It is also a good idea to put silk into a lingerie bag or pillowcase for washing so that it is not damaged by the washing machines agitator. Only use a detergent that suits the ties.
I had read that you could prewash silk in a washing machine. I learned this the hard way when I did the same thing as OPs friend mentioned in the thread. It is a natural fiber after all.
I just want to point out that STBH put this through the wash not me. A note about dye and washing machines. Apply a spot treatment to the tie if needed.
And the dryer too. Machine wash in cold water on a gentle or handwash cycle. Test a small hidden area on the fabric to look for any dye bleed or water stain let the tie dry to determine if.
Thus you should never wash it in the washing machine or handwash it with anything else as the dye could bleed out and stain other things. Use a mild detergent designed for delicate fabrics. Bleach can turn a white tie yellowish If your washing machine does not have these settings or if your tie seems extra delicate hand wash the tie in cold water with a small amount of laundry detergent.
Add the homemade laundry detergent into your washing machines detergent dispenser. Some silks are safe to run through the washing machine. Only wash silk items with similar colours to help avoid colour run.