Hi Julie, I have a copy of a "Will" of Ebenezer Briggs of Rome, NY who mentions his brother Joseph. I am not positive that this is your Joseph, but might be worth a try to find out. Ebenezer was b. 1773 in VT, so the ages seem right.
Even better, there is a "Will" for Joseph too, but I haven't ordered it yet. Email me if you would like to discuss this further.