Web MD is a great resource for evaluating symptoms.
I understand stubborn and of course there is a risk in not seeking immediate medical attention. There is also a tendency to imagine the most horrific diseases when conjuring the what ifs. Our body's immune system when working properly takes care of us amazingly well and some of the diseases suggested while real possibilities are still quite rare in frequency. Superbugs tend to be in metropolitan areas and the hospital, tetanus however is a bacteria that lives in the soil, so we kinda run into it a lot.
This is from kidshealth.org, that is where most husbands need to look. "If you get a deep or dirty cut or a puncture wound and it's been more than 5 years since your last tetanus shot, see a doctor so you can get a tetanus booster to ensure that you're fully immunized."
I hope your husband is much better today.