Dealing with unfeasible payments on Sallie Mae loan and mean help deciding on refinancing with cosigner

My little brother just finished college in December, and his loans for Sallie Mae are already due because he took one semester off and used his grace period at that point. He doesn't have a job yet and we can't afford the payments

We are a low-income family and honestly we were not well informed enough to go the federal loan route until his third year of college. We were not directed to anywhere to get info and we thought this would be the best option. We were unfortunately wrong and the payments for this with no income plan are just way out of our plans.

His Sallie Mae loans have a 16% variable interest. His total loans taken out were around $60k and he already owes 98k as they accrued interest while he was in school. Only about half his loans are in repayment now because of that semester he took off and the other half are due in July (6 months after his graduation date). His payments already total almost $1,000/month.

We are thinking about trying to refinance but can only refinance through providers that allow co-signers on the application. We tried So-Fi and he could not get approved alone. We were "pre-qualified" with Nelnet loans but obviously no guarantee we will actually get it and the payments were still way beyond our means and a 9% interest rate.

1. Do you have any suggestions on where to apply for a refinance including a cosigner?

2. Is there any harm in refinancing now and then refinancing again when he gets a job? We are assuming he could get a better rate at that point but not sure if we should just wait it out until that point

Any help is greatly appreciated!