Voy - I assume from your post that you purchased tech grade (80%) sodium chlorite from a chem supply company, and made your own Miracle-Mineral-Supplement according to the instructions in Humble's book - part 2. Is that right? Good for you! I did the same thing...
How much is he able to drink? If possible, try to get him to drink 3 - 4 liters of pure water per day.
If your detox symptoms are mild, and you feel committed to continuing on the Miracle-Mineral-Supplement protocol, then you will want to continue hitting the tumor as hard as you can. I know that there have been others who have used even more than 3 doses per day ... as much as hourly I think in order to hit the cancer hard. However, the in cases I have read where this was done it was a relatively healthy patient, younger people, with cancer.
Do you think that the tumor condition has become worse since starting on the Miracle-Mineral-Supplement ? The detox effects of MMS can be significant, and if your father is in poor health (other than the tumor), then his body may not be able to process the waste that results from the MMS. For example, if he cannot drink very much, then you must scale back the MMS.
This is a tough choice, because in the end the MMS is absolutely the best weapon to use against cancer (the Budwig diet it great in addition, though), if the body can tolerate it.