Like kilroyscarnival, I see the styles in the sent document and not the received.
The problem is apparently not in your document but in the receiving system.
Ask your recipient to:

1. Save your document to the local hard drive, not open from email.
2. Start Word in safe mode. Open Office apps in safe mode on a Windows PC - Microsoft Office
3. Open the document from within Word using File > Open.

Note, when I open the received document, I see the style as Normal1, not Normal. Both are present in the document but your custom styles are not.