Is it possible for someone who has a tourist visa to stay in the US until his/her change of status change to immigrant?

No. Your sibling cannot enter the United States with a tourist visa with the intent to remain here permanently. Your sibling also cannot remain in the country while waiting for an immigrant visa. To be able to adjust his/her status, your sibling would be required to maintain valid nonimmigrant status up until they could file an application for adjustment of status. It will take more than a decade for them to be able to apply for adjustment of status as he/she will need to wait for a visa to be available if petitioned by a sibling. You can read more about family-based immigration at http://myattorneyusa.com/family-immigration.