Then again, for the sake of argument, by the concept of what "God" is he can do anything so the answer would be yes. For the sake of argument, lets assume he‘s real. Just because such a being decides not to answer every prayer in a way we know of, for whatever reason, doesn't mean he can't do it. Trying to disprove something like that by lack of evidence of existence isn’t a sound method. All it can prove to those people that try to do so is at best they know nothing. For the sake of argument an omnipotent, omnipresent, and omniscient being can do a lot of things science tells us we will most likely never be able to do. So could those things be accomplished though the power of prayer, no? Could they be accomplished by the thing that people believe answers prayer? I guess people's answer to that depends on what one believes of a higher power.