  In this paper, we compute basis elements of certain spaces of weight 0 weakly
holomorphic modular forms and consider the integrality of Fourier coefficients
of the modular forms. We use the results to construct automorphic correction of
the rank 2 hyperbolic Kac-Moody algebras H(a), a=4,5,6, through Hilbert modular
forms explicitly given by Borcherds lifts of the weakly holomorphic modular
forms. We also compute asymptotic of the Fourier coefficients as they are
related to root multiplicities of the rank 2 hyperbolic Kac-Moody algebras.
This work is a continuation of the previous paper, where automorphic correction
was constructed for H(a), a=3, 11, 66.
