What Urbanprep said is true. However helping your neighbors while still obtaining OPSEC about your prepping is ideal. Have friendly conversations about an approaching storm or other short term disaster situations. Ask them the question, what do you think I should do before this storm arrives, it might be a bad one? Then add onto whatever advice is givin.
You can then privately store some extra personal water filters (a neighbors entire family can survive with one for a considerable time. Store an extra few hundred pounds of white rice, it's cheap and stores very long time. Clean water and rice supplemented by small game and foraged edibles can sustain your neighbors for months after whatever food supplies they had is gone.