Kindly refer to the following link(s):
What is the best thing to do for a deceased person ?
Is it permissible to transfer any and every sort of good deed to the deceased?| Sheikh Assim AlHakeem
What can children do to benefit their deceased parents? | Sheikh Assim Al Hakeem
What can I do to benefit a deceased loved one?
Feeding the poor to give reward to the deceased
Congregational dua, 40 days, Quran for dead..permissible? How to benefit our deceased?quran khani or khatam