Will a stool softener help with an elderly person?

Sure, but... Docusate (per pdr) helps moisten & soften hard, dry stools. It is not a true laxative, but facilitates natural defecation, usually within 12 to 72 hours. This is safe & available for anyone over 2, & assumes normal GI anatomy without inflammation, stenosis, extrinsic or intrinsic obstruction. Gi motility in the healthy elderly patient is really little different than in younger patients.