What is the actual dose of MMS if you share it with a family member?

If I prepare a 1 drop dose and drink half, is my dosage considered to be only 1/2 drop MMS or still a 1 drop dose?

Since you did not ingest half of a 1 drop MMS1 dose, you drank a 1/2 drop MMS1 dose. The Starting Procedure Protocol describes how-to-make a 1/4 drop dose, etc.

When you cut a MMS1 dose in half, you get one half of the chlorine dioxide (CLO2) that was in the full dose, or that would be available in a stomach with normal gastric acids. Most of the available CLO2 should be released from MMS in your stomach.