Since your husband is neither selling goods nor providing services in exchange for this stipend, it is my professional opinion that it is not self-employment income, notwithstanding that it is directly related to his main line of work.
I believe the income should be reported as Other Income on Schedule 1 (Form 1040), line 21. It will be subject to income tax, but not FICA self-employment tax.
Reporting 1099-MISC that is
not self-employment income
Under the Wages & Income tab (or Personal Income tab in TurboTax Home &
Business) scroll down to Other Common Income.
Select the start/update button next to Income from Form 1099-MISC. Then click YES to
indicate you have a 1099-MISC.
Enter the 1099-MISC
exactly as printed, and then Continue.
Enter the reason you
got this money – be it scholarship, bonus, apprenticeship stipend, etc. Click Continue.
Select None of these
apply, then Continue.
Select No, it didn’t
involve work…, and click Continue.
Select ONLY the tax
year for which this specific Form 1099-MISC was issued. Do not select the year
that you received the 1099. Select the year for which the 1099-MISC was issued.
Click Continue.
Select "No, it
didn’t involve an intent to earn money," then click Continue.
Select No, then
click Continue.
Click the DONE button, and that does it.