How can I apply for Portugal's D7 visa with a dismissed criminal record?

The described situation must be carefully analyzed under the Portuguese legislation in order to access if you are compliant with the requirements.

If you request a criminal record certificate and it comes with no conviction, that should be enough. If the applicant has been found guilty of a crime which is also punishable under the Portuguese law, it would be a problem.

One can only apply for a temporary residence permit under the D7 Visa if one is not convicted of a crime in their home country that in Portugal’s law would have a one year imprisonment sentence. If this criteria is not met, the application for a temporary residence permit will most likely be refused by the Portuguese authorities. The maintenance of a property where marijuana was stored 14 years ago should not prevent your husband from applying as the crime is already time-barred. However, please check this information with your local authorities, consulate or embassy, and request for the removal of this criminal information from his record due to the time passed since the crime was committed. If your husband’s criminal record has no registered convictions, it is likely that his application for a temporary residence permit in Portugal would not face any issues.

Regarding the Visa, the criminal record requirement is the "absence of conviction for a crime that in Portugal is punishable by deprivation of liberty for more than one year". Meaning it depends on the time of the penalty. So, to check the eligibility for the D7 visa, each criminal conviction must be analysed and the penalty compared with the Portuguese criminal law.