Explicitly, as a free module over the ground ring $\mathbb{M}_2$:
$$H^{\ast,\ast}(\text{Gr}_1(\mathbb{R}^{12,1}))=\mathbb{M}_2\oplus\Sigma^{1,1}\mathbb{M}_2\oplus\Sigma^{2,1}\mathbb{M}_2\oplus\Sigma^{3,1}\mathbb{M}_2\oplus\Sigma^{4,1}\mathbb{M}_2\oplus\Sigma^{5,1}\mathbb{M}_2\oplus\Sigma^{6,1}\mathbb{M}_2\oplus\Sigma^{7,1}\mathbb{M}_2\oplus\Sigma^{8,1}\mathbb{M}_2\oplus\Sigma^{9,1}\mathbb{M}_2\oplus\Sigma^{10,1}\mathbb{M}_2\oplus\Sigma^{11,1}\mathbb{M}_2.$$