Sorry to read the negativity in this thread for what is essentially a humanitarian offer.
I have no links with Africa, but thinking around the problem, how about
:
- Sticking to one country
- Validating your license there
- Buying/leasing an aircraft 'in country', then selling afterwards?
It's a vast continent, and I’m sure that this might make it easier to volunteer your services.
Good luck, and thank you.