Some embassies seem to be worse than others and will deny almost everybody. To try to get a temporary visa, he will need to show stronger ties, more reasons why he will not overstay in Canada, family, assets etc.
You can probably complain about the embassy to immigration but since this is very common, I doubt it will matter much. The embassy will only say that they looked at his profile and found him likely to overstay and hence he can't get a visa.
If he wants to immigrate, he can look into federal investor class immigration or he can look into provincial business class which is probably faster.
About all PNP Business Classes also require a visit before issuing nomination so problem still exists that how OP shall get a visitor visa even if he/she apply through provincial business class