Well, 1.6 AU is pretty far, similar to Mars' distance to the Sun. The yellow star is also only a G8V. It might only give the planet similar amounts of heat as the asteroid belt gets, and it's quite cold there.
It would also be getting heat from the brown dwarf, though, which is distributed between the near and far sides by the atmosphere.
I recall reading an interesting article a while back about the projected heat distribution between the day and night sides of tide-locked planets and it's quite complex. If there isn't enough heat transfer the planet will suffer "atmospheric collapse" when the temperature at the far pole drops below the freezing point of the primary greenhouse gas of the atmosphere (usually carbon dioxide). The atmosphere starts snowing out, which makes it thinner and reduces its greenhouse effect, which makes the far pole even colder, in a feedback loop that eventually leaves the planet airless.
If the planet doesn't have enough water for an ice cap that reaches out of the cold trap, or an ocean to circulate heat from the near pole to the far pole, it can also lose its liquid water in a similar manner.