'riches' without any qualification does normally mean money - but by contrasting it with 'while' - you have to assume when reading it that 'riches' means non-monetary enrichment in the first part. It's a bit of a trick with words. In the second, they are saying - well actually - it's both (the 'normal' monetary kind, and the non-monetary one previously implied. I guess they are saying that friends also help you make money, which, based on the other saying 'it's not what you know, it's who you know', does make sense.

Riches generally relates to wealth , but It can also means something valuable to possess as in riches of life . There is spiritual riches as well ( just google "spiritual riches" and "riches in life" and you will get many hits)