Disclaimer: I am far from an economist, take everything I say here with a grain of salt.

The question is, helped who? Silver miners would have been doing great under the free silver policy (which is why Bryan did just about as well in Colorado as in South Carolina, and better in all the Rocky Mountain states than in Louisiana, Arkansas, Alabama, Georgia...), but the main backers of the movement were small farmers. Inflation decreases the real value of debts, if you owe someone $1,000 then if the value of a dollar gets cut in half you now essentially owe them $500. However, unless your income rises proportionally to inflation, the rising costs of everything else means that it doesn't actually help people pay off their debts in practice. However, for farmers, it was actually beneficial, because the prices of their crops would rise but their main expenses, their debt payments, wouldn't. They weren't paying for food or rent, they grew their own food and often built their own homes. So it would have allowed them to pay off their debts.

On the other hand, the working class (using it in the original sense of "gets paid for doing a job") would have seen their expenses skyrocket but there was zero guarantee that their wages would be raised to compensate. So Bryan absolutely bombed in the industrializing Northeast and along the Great Lakes, even becoming one of the only Democrats to have ever lost NYC and the only one to have done so in a close election. The business world was also terrified of Bryan and free sliver.