A better example is Sri Lanka. No country, not even IMF, came to their rescue when they needed it the most. China came with fancy projects when Sri Lanka was regarded as best economy in South Asia, India came with foods and energy when their economy is the worst in the world. This is after knowing that Sri Lankans including their general population look down on other countries in South Asia including India and Bangladesh.
Human nature I am afraid to look down on people less wealthy than you.
Both India and BD have helped Sri Lanka with currency swaps, foods and energy when they were at their most vulnerable and I am sure that the common Sri Lankan will know who their well-wishers are now.
Anyway it is in both India's and BD's interest to have a stable and prosperous S Asian region. So not just altruism there.