It's true that memories of the atrocities carried out by Pakistan in Bangladesh are fading with time, and now Bangladesh seeks to maintain relations with Pakistan as with any other normal country. However, Bangladesh's relationship with Pakistan will never come at the expense of its strong ties with India. Bangladesh has nothing to gain from Pakistan joining BRICS, and if they support Pakistan, it could certainly harm their relations with India. As for Iran and Afghanistan, they are unlikely to vote for Pakistan for obvious reasons.
Your reading of the situation is wrong, Afghanistan doesn't even have a recognized govt, idk why you keep mentioning them and BRICS in the same sentence. Iran has no animosity towards Pakistan. A Bangladesh has quite a bit to gain from Pakistan.
There are several Bangladeshis who see prospects in that relationship.