First of all, the parishes I attend are huge and there are a lot of members who are still working “essential jobs” as designated by the state, such as police/ fire, EMT, medical personnel, various manufacturing, takeout food, grocery store staff etc. These people are getting swamped with work on their regular jobs in which they are helping the community, so they’re not going to be able to do extra volunteer stuff.
Second, the parishes I attend have regular social service ministries to the poor that they are carrying on to the extent they can do so under the state requirements. For example, the day care obviously had to close because mandated by the state, but probably some of the other stuff like the food distribution to the poor and the delivery of the meals to the homebound seniors can and will still go on, with appropriate precautions so as not to spread the virus. Obviously if a senior citizen is depending on someone bringing food for them to eat, that can’t just stop, the person will not have food.
Third, since the restriction on Masses just happened on Wednesday at noon which is less than 2 days ago, the churches are still working out what more they can do to help in some cases - probably checking on elderly and homebound will be a big part of that.
Fourth, the churches are still open for private prayer, some are having Adoration, etc. so even though the Masses are suspended, there’s still opportunities for worship activity.