When Hurricane Katrina hit New Orleans, governments from around the world offered aid to the U.S. One of those offering aid was the government of Bangladesh. I don't recall the exact amount but it was more than token and not insubstantial for a poor country.
Now the Democratic Republic of Congo (considerably poorer than Bangladesh, I'm quite sure, though I haven't checked the figures) is offering aid to Haiti in the wake of the earthquake. A Congolese political scientist is quoted by the BBC as saying: "It's a contradiction to see a country which is facing serious financial problems giving away $2.5 [million] but at the same time, it's a purely diplomatic reaction, the Congolese government wants to appear like any other government." (emphasis added)
I think that is exactly right. Offering aid in disasters has become something that sovereign governments -- or governments that want to appear as fully sovereign as any others -- do. It has become a norm of modern sovereign statehood, virtually in the same category as having a national airline and opening embassies in other countries.
The Congolese government's offer of aid is a way of telling the world that it has its problems under control (even though it almost certainly doesn't) and that it deserves as much respect as any other member state of the U.N.
(And I bet you thought that having studied IR theory was a completely impractical waste of time, didn't you? Hmm, I think I'd better not go further with this...)