Conveying the reward of good deeds to the deceased

Q: If a person recites some portion of the Qur’aan and thereafter conveys the reward of the recitation to a deceased, will the reward reach the deceased and will the deceased benefit through the recitation? Some people claim that neither does the reward reach the deceased nor does the deceased benefit from the recitation in any way. They claim that this is proven through the verse of the Qur’aan

وَ اَنۡ لَّیۡسَ لِلْاِنۡسَانِ اِلَّا مَا سَعٰی

And man does not deserve but the reward of his own actions

Is this claim correct? Is there any proof or evidence in the Mubaarak Ahaadith that the reward of the recitation reaches the deceased and the deceased benefits through it?

Holding one's mother's head and taking a qasam

Q: I did a job in Saudi Arabia. On my vacation my mom came to know that I am connected with a girl (na mahram) with love. My mother told me to put your hands on my head and take a "qasam" that you will not talk to your lover in future and you will forget her. I did as she said with intention that I will follow her qasam. But I came to know that this type of qasam is haraam in Islam, so what is the worth of that "qasam". Could I break that? or my mom has to take beg for forgives from Allah because my mother never mentioned the name of Allah in her qasam? Please answer me soon as possible.