OK not to show to brother's deceased wife's sister's granddaughter's baptism? ( I chose to celebrate my own daughter's birthday w/her)?

should have added that the baby's mother noted that my daughter should come&celebrate the baptism&her birthday with these strangers

Yes, do not go unless you want to,the baby is nothing to you.

thats up to you what you want to do

Not if you said you would.

A person can have peace in their family by reciting daily and with care 7 Hail Marys, one each while meditating on each of the Seven Sorrows of the Virgin Mary. Further information about this devotion is available online.