Jimmy and Chuck's mom is shown in a hospital bed. The cardiac monitor shows her heart's rhythm. There are a couple of normal beats followed by two pacemaker stimuli. The heart doesn't respond to the pacemaker stimuli, meaning that her heart is starting to fail. When she does pass away, a shot of the monitor shows a flat line. However, the pacemaker stimuli should still be present since her heart is no longer beating - that's what pacemakers are designed to do. They probably decided not to show the pacing stimuli to avoid confusing laypeople in the audience.
Chuck covered the walls inside his home with space blankets. Such blankets are made of aluminized, biaxially oriented polyethylene terephthalate (BoPET) which is a polyester film made from stretched polyethylene terephthalate (PET) and is an excellent electrical insulator. However, it will not protect from electromagnetic radiation. It will not protect from electromagnetic fields that are produced by the current that flows through electrical devices.