mother & son were doing drugs together. The mother is the one by the toilet. She was so stoned that she fell in the bathroom unconcious at first they feel, beccause she showed signs of trying to get up, before going unconcious. She died within a couple minutes of collapsing.
The son, extremely stoned, somewhat aware his mother did not come back, went into the bathroom & found her dead. Already stoned, he was not in any shape, to think anything through logically. He proped himself down & poped a handful of drugs he still possessed & died beside her.