The CPU support list (http://www.cpu-upgrade.com/mb-Intel/DH61HO.html) shows only i5-2400S (http://www.cpu-upgrade.com/CPUs/Intel/Core_i5/i5-2400S.html)
Yes it will. The Intel DH61HO supports CPUs with an LGA1155 pin-out (e.g., 2nd-gen Sandy Bridge CPUs). Both the Pentium G630 and the Core i5-2400 have LGA1155 sockets belonging to the same 2nd-gen Sandy Bridge Intel CPUs.
The CPU support list (http://www.cpu-upgrade.com/mb-Intel/DH61HO.html) shows only i5-2400S (http://www.cpu-upgrade.com/CPUs/Intel/Core_i5/i5-2400S.html)
Intel's specs for that mobo list a supported CPU TDP of 65W. http://ark.intel.com/products/66983/Intel-Desktop-Board-DH61HO
The 2400S is 65W, but the 2400 is 95W. The 2400 may work in terms of being able to install and run with it, but the motherboard isn't rated to supply sufficient power.