I have already acquired only one session of the gardasil vaccine this was 3-4yrs ago, he has warts but I don't haven't had an outbreaks just cancer?

HPV causes cancer. Please start over. It may be of benefit. Get all three doses on time. I do not know what the real pap smear results are but there is growing evidence that hpv vaccine can be of assistance in preventing progression of disease.
Gardisil. Gardisil requires three vaccines. You did not actually ask a question, but you are not protected without three vaccines.
Please finish series. The gardisil includes 4 strains, 2 that involve visible warts and 2 that are associated with cancer. If you complete your series you can protect yourself from strains which you have not acquired so far. His warts strains are a cosmetic more than a cancer worry, but he may carry non wart strains.You should have regular pap tests in the future regardless of vaccine use.