His visa will still be valid under the scenario you stated, but you would have a continuing obligation to support him as promised. Also, how will you be able to adjust his status to that of a permanent resident if you no longer have income to support him? You may have to rely on a joint financial sponsor. Also, there are many issues that the Embassy reviews in fiancé cases. I highly recommend having an experienced immigration attorney represent you and your fiancé.
If you have any questions regarding immigration, please feel free to call me, immigration attorney Shawn Mesa at (813) 679-5780.
Disclaimer: This information is provided as a public service and not intended to establish an attorney-client relationship. Any reliance on this information is taken at your own risk.