He can’t see the forest for the trees.
More Traditional Proverbs:
Cold feet.Traditional
There will be sleeping enough in the grave.
Traditional
Seeking happiness is a straight way to misery.
Traditional
Bless my weeds.
Traditional
Money is best when acquired by one's own hands. It is not so good when inherited. It is bad when it is a brother's. It is worst when it is a woman's.
Traditional
Attitudes are contagious. Are yours worth catching
Traditional