Hello, i'm gaining experience in familiar problems, so i think i could help you.
My diagnosis is this: this guy's mother is being possesed by negative energies, caused by her childhood (maybe a bad one), emotional problems with her friends, parents, husband or boyfriend. She has let this problems overwhelm her, causing she absorb the negativity of those. The consecuence: being possesed by negative forces, that's why she is horrible.
My prescription is this: First of all, this guy will have to make a line salt at his door house and in his door room. The salt will avoid any negative energies come in.
Then he will proceed to purify his mother. In this case HIM or YOU will fill his/your heart with love, his mother has just lived a bad life or bad moments that have made her cry and anger a lot. After this HE/YOU will do this chant at any day of the week:
Ingredients: 1 white candle, 1 incense (any), 1 table to set the candle and the incense and 1 white cloth to cover the table.
Instructions: Set the altar, light the candle and incense.
Sit, stand or kneel (be sure it's confortable) and chant 9 times:
Tela, wuton we wel thair;................
I advice repeating this process 3 times in 3 days. So, it will be 3 times the ingredients you will get.
Results can be noticed after the next day of the first ritual, and so, starting the purification, the mother will need to be talked to, not just ignore her.
Any questions, mail me. Blessings!