Is a person held accountable for the sin of backbiting upon their death, and does the arrival of the angels of mercy negate the torment of the grave?

"A human sins and errs, and blessed is he who hastens to repent. Backbiting is among the grave sins, and underestimating it is dangerous, as it is one of the causes of torment in the grave. Torment in the grave is not limited to backbiting and urine, but these are more prominent in that regard. So, whoever angers Allah by committing sins, does not repent, and dies upon that, will experience torment in the barzakh according to the extent of Allah's anger and displeasure. The fact that a person is among the people of Tawhid does not negate the possibility of them being tormented in their grave, but their torment is less than that of a disbeliever, and their ultimate destination is Paradise. A sincere Muslim strives to avoid what incurs Allah's wrath. The soul of a believer is taken by the angels of mercy, and even if they are a fasiq (transgressor), their tidings are according to their state, and this does not negate the possibility of them being tormented in their grave for some of their sins if Allah wills."