I recently had to explain to my early-twenties son why he and his friends shouldn't view tax season as a competition to see who can get the biggest refund.
People only get a tax refund if they overpaid during the course of the tax year. The default rates of paycheck withholding provided by the IRS for employers to use are intended to produce pretty close to the right amount. In his situation it's unlikely TurboTax missed a deduction or credit he's entitled to (assuming you answered all the questions accurately, of course). So a small refund means everything worked as it should. That's a Good Thing.
If for some reason he specifically wants a refund next year, he could give his employer a W-4 now, asking them to withhold a little extra from each paycheck in 2022, but unless he expects to have some other source of income which isn't being taxed directly, he would effectively be giving the government a free loan of his money until next tax season, so it isn't a very good strategy.
