AUGUSTA — A man, down on his luck, moved in with his elderly grandfather. He ran up his grandfather’s phone bill, used his car and didn’t pay for gas.

One day the grandson simply left, taking his grandfather’s car with him but leaving his own cat behind. The grandfather was too kind to give the animal away.

Eventually, the grandfather faced eviction. He couldn’t pay his rent. So he moved in with his son, who allegedly had abused him verbally before.

That story was recounted by Kristin Overton, director of Bridges Home Care in Augusta, in written testimony on a bill that seeks to give the elderly more protection from financial abuse — an issue that is expected to mushroom as the state’s population continues to age.

The bill, L.D. 527, sponsored by Rep. Mark Dion, D-Portland, a former Cumberland County sheriff, passed in the Maine House of Representatives on Tuesday. It now awaits votes in the Senate. It would clarify state law to say those with dementia and other cognitive impairments are unable to consent to financially abusive conduct by caregivers that would be criminal without the consent defense.

In the state aging plan, released in 2012, the Maine Department of Health and Human Services said 1 in 5 Mainers over age 65 have been exploited financially by family, caregivers or scammers.

Dion, a former police officer who is now a lawyer, said that as an investigator he often walked away unsatisfied from unprovable cases involving elders. Often, many seniors couldn’t “consent the way the general public understands consent,”