  The stability of three-dimensional relativistic semimetals to disorder has
recently attracted great attention, but the effect of disorder remains elusive
for multifold fermions, that are not present in the framework of quantum field
theory. In this paper, we investigate one type of multifold fermions, so-called
triple-point fermions (TPFs), which have pseudospin-1 degrees of freedom and
topological charges $\pm2$. Specifically, we consider the effect of disorder on
a minimal, three-band tight-binding model, which realizes the minimal number of
two TPFs. The numerically-obtained, disorder-averaged density of states
suggests that, within a finite energy window, the TPFs are robust up to a
critical strength of disorder. In the strong disorder regime, the inter-TPF
scattering is the main mechanism for destroying a single TPF. Moreover, we
study the effects of disorder on the distribution of Fermi arcs and surface
Berry curvature. We demonstrate that the Fermi arc retains its sharpness at
weak disorder, but gradually dissolves into the metallic bulk for stronger
disorder. In clean limit, the surface Berry curvature exhibits a bipolar
configuration in the surface Brillouin zone. With increasing disorder, the
positive and negative surface Berry curvature start to merge at the nearby
momenta where the Fermi arcs penetrate into bulk.
