The best way to help them now is to send arms, but that if of course if you can get them through the border.
Belarus knows that they can't trust army drafted from regular men, and that's why the army was sent off to seal the borders, while the special police monsters are let to keep doing their atrocities inside cities.
The West is also unwittingly facilitates this by keeping shutting down attempts to get arms to Belarus from Balkans.
It's now in the news, but Poland, a NATO member, has already shut a third attempt to get arms to the country, despite Warsaw itself being the one initiating this with Belarus opposition.