We have calculated Coulomb, exchange and configuration-average ionization energies for the ground and excited configurations in helium atom confined by a spherical cavity of finite barrier height. In addition, we have carried out kinetic energies, nuclear attraction energies, confining potential energies and probabilities of finding the electrons that occupy different subshells. In the strong and intermediate confinement regions, the results show that the barrier height of potential well and dot size have a strong influence on the energies and probabilities. The kinetic energies of electrons in 1s and nl orbitals increase as the height of the potential barrier increases, but in nuclear attraction energies the opposite behavior occurs. It is found that Coulomb and exchange energies rapidly decrease after the critical confinement radii, in which the electron in nl orbital escapes out of the well. The configuration-ionization confinement radius depends strongly on the potential barrier height.