My parents are getting older and it's getting difficult for them to go to the bank or ATM regularly. Staying in a different city I feel bad I can't help them out. Does anyone know of a reliable way of getting cash delivered to doorstep?

Banks have such services, generally outsourced to partner firms. Talk to your RM/ branch. There will be minimal delivery fee. This is also mentioned in the booklet that comes with account opening

Be with your parents. That’s the best help you can do to them

Both Govt and Private banks offer door step services specially for the senior citizens/ elderly. Most of the govt banks offer it without additional cost. Some private ones also offer this with no additional fees. Check it with your bank or relationship / branch manger

Money order ?

Tell your friends to do it if it's your hometown or someone you trust.