He should have buried the bodies and kept his mouth shut.
That might have been his intent, up to the point where the police visited his house and asked if he had seen the two, whose car was parked up the block.
I'm sure that entered his mind but he couldn't get the bodies out of the basement without help. That may be why he called his brother after it happened to come down to help him.
He never contacted the police, so it seems that his plan was to conceal the murders.
Of course, it's hard to carry two bodies upstairs from your basement, and hard to dig a grave in a Minnesota winter. It's also hard to dig a grave on your property when you have neighbors. It's hard as well to get rid of a red Mitsubishi without anyone noticing it either.
Your advice, immoral as it is, is also extremely impractical.