whether he

"......In all the difficulties which will arise in life, fling yourself down on the truth and cling to that as a drowning man in a stormy sea flings himself on to a plank and clings to it, knowing that, whether he sink or swim with it, it is the best he has. If you become a man of thought and learning, oh, never with your left hand be afraid to pull down what your right has painfully built up through the years of thought, brooding and study, if you see it at last not be to founded on that which is; die poor, unloved, unknown, a failure perhaps in the eyes of the world—but do not shut your eyes to the truth as you keep it alive in your own soul."

Hello,

Can you explain if the highleted parts in the paragraph are correct?

1. Don't you think an "s" is required after the verbs "sink" and "swim" that's: "whether he sinks or swims with it."

2. "not be to founded". I don't understand this.. (the structure) is it a typo?



Thank you in advance