Is what you wrote above the 'proof' you are referring to? That won't even begin to be sufficient, what you wrote above sounds like not much more than a poor relationship. Even that, he would probably be able to explain lack of communication as being nothing more than busy.
This is the problem: for them to act on it as a clear case of marriage fraud, the proof needed would likely have to be close to the proverbial smoking gun - e.g. written messages from the alleged fraudster saying his intentions were fake and he just wants to get PR status.
And to be a bit blunt: in a lot of respects, how is this the government's fault? Canadian residents in Canada get in bad relationships and marriages all the time where one partner has large monetary losses, apart from laws allowing a plaintiff to take the 'bad' partner to (civil) court, the government doesn't get involved. Except, of course, where there is actual criminal behaviour, where the standards of proof are quite high - and this applies equally to sponsored PRs, for whom criminal behaviour can also mean revocation of PR status and eventual deportation. No outright criminal behaviour? The PR is a PR, period, with the same rights as other PRs.
Sponsors are taking on responsibility for their spouses. Many don't seem to fully understand this.
And let's face it: the risks of a fraudulent marriage for immigration purposes are higher with arranged marriages. That's not a comment on arranged marriages generally, but that those entering into them need to be MUCH more careful.