The hydrodynamics and rheology of a sheared dilute gas-solid suspension, consisting of inelastic hard-spheres suspended in a gas, are analysed using anisotropic Maxwellian as the single particle distribution function. The closed-form solutions for granular temperature (T ) and three invariants of the second-moment tensor are obtained as functions of the Stokes number (St), the mean density (ν) and the restitution coefficient (e). Multiple states of high and low temperatures are found when the Stokes number is small, thus recovering the "ignited" and "quenched" states, respectively, of Tsao & Koch (J. Fluid Mech.,1995, vol. 296, pp. 211-246). The phase diagram is constructed in the three-dimensional (ν, St, e)-space that delineates the regions of ignited and quenched states and their coexistence. Analytical expressions for the particle-phase shear viscosity and the normal stress differences are obtained, along with related scaling relations on the quenched and ignited states. At any e, the shear-viscosity undergoes a discontinuous jump with increasing shear rate (i.e. discontinuous shear-thickening) at the "quenchedignited" transition. The first (N 1 ) and second (N 2 ) normal-stress differences also undergo similar first-order transitions: (i) N 1 jumps from large to small positive values and (ii) N 2 from positive to negative values with increasing St, with the sign-change of N 2 identified with the system making a transition from the quenched to ignited states. The superior prediction of the present theory over the standard Grad's method and the Chapman-Enskog solution is demonstrated via comparisons of transport coefficients with simulation data for a range of Stokes number and restitution coefficient.