If you smell that smell, it is already dangerous.
A certified electrician or home inspector using an infrared (heat seeking) camera or a laser thermometer can locate any overheating electrical components inside the walls before it gets worse or before your home burns down while your family is asleep. The electrician can remove outlet covers in the area where you smell the smell and inspect the electrical wires inside.
Once you have identified the problem to a switch, socket, outlet etc. do not use it again without having an electrician check it because it may have melted enough that any further use will start a fire. The electrician can inspect it to see if it is safe or if you should placed the outlet or fixture before you continue to use it.
Be sure to read these other posts on here about that stinking odorFishy smell in house
P.S. One more thought….If you suspect it is coming from a family member there IS a metabolic disorder that causes one to give off that odor. Trimethylaminuria (TMAU), an uncommon genetic disorder that causes a strong body odor that some describe as smelling like rotting fish, feces or garbage is created when the body is not able to break down trimethylamine.