It happened just before 9:00 a.m. on the 200 block of Oakland Place in Upper Gwynedd.
Police say an 86-year-old man was at home and began arguing with his 82-year-old sister-in-law, who had come to the house to help him with medical issues.
During the course of the argument, police say the man grabbed a pair of scissors and stabbed the woman numerous times.
Medics took the woman to Lansdale Hospital. She was treated for minor stab wounds and is listed in good condition.
Officers took the man to the hospital for a psychological evaluation.
Police say he will be charged.
There was also the odor of gas in the home, which initially caused alarm. However, it was quickly determined that the leak was caused by the pilot being out on the stove.
The identity of the two victims have not been released.
The investigation continues.
