NARRAGANSETT — Senate Majority Leader Michael McCaffrey has been on both sides of the fight to allow homeowners to build "in-law apartments" on their properties for their elderly and, in some cases, ailing relatives. In two years, he's gone from champion to not-so-happy neighbor of a proposed "accessory family dwelling unit" next door to his summer home in Narragansett. The law was hailed at the time as a key piece in the Senate's “Building a More Vibrant Rhode Island” package and a way to address the state's housing-affordability crisis. Now McCaffrey, who represents Warwick at the State House, is fighting the effort of his summer neighbors in Narragansett to expand their detached garage to build a living space for the husband's 98-year-old father.