If somebody wants to use the federal exception to sponsor one other relative, I assume they will ask you if your parents are alive and they may ask for their death certificates. Even if they don't, do you honestly want to claim to immigration that your parents are dead if they aren't? What if they want to apply for a visa to visit you? You will try to explain to immigration then that they came alive again? I strongly advise you not to lie to immigration. It can come back to haunt you, and it can even cause your PR to be revoked.
If his parents are truly dead and he is not married, has no children, no close relatives in Canada and no close relatives elsewhere that he can sponsor, he could use the federal exception to sponsor one other relative such as an adult nephew or a niece or a cousin, adult sibling etc.
Under PNP, he can sponsor certain relatives even if he has close relatives in Canada or elsewhere. The federal system purpose is to reunite families but the PNP purpose is more to bring skilled workers into the province. Therefore, they require that the sponsored person should have job related training or education and some work experience and in SK, you also need a job offer in your field. After having completed the sponsorship of one relative under PNP, he can sponsor another and another as long as they fulfill the requirements of the program and as long as they all stay in that province.
If IELTS is required, they will not accept a 3 year old score and for the most part, immigration likes General training over Academic but you should wait until your relative is really living in one of those provinces for one year and then see before they are going to sponsor you if IELTS is required under that immigration class. The rules can also change between now and then. If IELTS is required, then you simply take it.