You should ask Social Security if filing separately would restore your husband's Social Security benefits. They have their own rules which are outside the scope of this part of the TurboTax Community. In my experience, his payments will return to their old level after a specified period of time.
Married Filing Separately is an unfriendly tax filing status - it has the highest tax rate and many deductions and credits are limited or unavailable. You might end up paying more in taxes than you would gain by increasing your husband's Social Security payment.