Can we go to Mexico and return?

As long as the visa your husband has says it is "multiple entry" , then he may visit Mexico and re-enter the U.S. Actually, australia is on the visa waiver list , so your husband can visit the U.S. for up to 90 days without a visa...and people who come under the VWP can specifically visit Mexico and re-enter the U.S. See site below and read this paragraph which is several paragraphs below the graph listing the countries.

"VWP travelers who have been admitted under the Visa Waiver Program and who make a short trip to Canada, Mexico or an adjacent island generally can be readmitted to the United States under the VWP for the original admission period. "

Mexico recognises the US and Australia as countries with passports they can validate so no visa is necessary. There is a need to have proper travel papers and usually the airline flying you in will provide these (you often have to show your return ticket - depends on the border guards' tempers at the time!).

There was a special "tourist zone" just across the border for bus or car based tourists but this may have disappeared - check the immigration websites below.

im doing this in school and we watched a video bout it, it showed people getting out of mexico to the US and they get through pretty easy and get back easy aswell.

better call customs first ddd hello from JAY THERE GETTING PRETTY WEIRD OVER THE BIG WATER BETTER SFE THAN SORRY JAY