Aside from any possible moral issues … legally you are required to pay your rent. If he receives rent and does not use it to pay mortgage he may be in violation of rent-skimming laws.
I would only cease making payment if I was very near the end of my lease, so as to minimize any potential negative ramification of breaking my lease.
The owner may be in NOD status as a strategy to work out a short sale, or a work out. Properties often times receive NODs, then are brought back to date and then receive another NOD down the road. I would not expect to be in imminent danger of being evicted as a result of foreclosure in April.
