@Elmithian
She's living in her dead husband's house and has daughters from both marriages, so if she remarries the property should still go to either herself, her new husband, or her dead husband's progeny (Cindy), I think? If it's an issue of females not allowed to inherit she'd lose the mansion either way so Gary doesn't need to pull this bs.
Though I guess it's possible he's obligated to support her (financially) as her brother and he wants to hand her off to someone else as soon as possible, idk.
@lukcluck
I thought the suitors look too weak/un-influential for this move, but I guess it's possible they have some connections behind them. Author probably made them look useless so that ML can look cooler by contrast.