The classification of small business loan should not change for CRA Small Business Reporting even if the proceeds are to be used for assistance during a disaster.
Look at it this way, if a loan is not CRA Small Business/Farm reportable (due to dollar amount being >$1,000,000) then review the loan in the disaster area as you would a loan in a low or moderate income or middle-income distressed census tract documenting how is stabilizes the geography. The activity could occur in an upper income census tract but if funding goes to improve the infrastructure of a disaster area then it should count as a CDL.
Separately track information about the loan of which concessions were made in interest rates and present to the regulator during your next CRA Exam. I look at this as a community development service and the examiners may make special mention of this activity in your CRA PE.