I think in this case "fostering" is technically a gerund. This is a word that is usually used as a verb that is instead being used as a noun. Another example might be: She enjoys running. The verb in the sentence isn't "running" (even though that word is generally used as a verb), rather it is "enjoys".
Yes, it's incorrect. You could say "he is learning more about nursing" and "he is learning more about caring", but not "he is learning more about concerning." Here the noun form is "concern". So, "he is learning more about concern" or "He is learning more concerning care" or "He is learning more concerning soccer" but you can't stop at "concerning."