"I wish to go to her place too but my relationship with my father in law have turned sour."
So what? You're there to see your son. You can pick your son up and take him somewhere. It's your child, not his.
"I have asked her to let me bring him back on Friday night and bring him back on sat evening but she don't agree. He mention our boy is too young for me to handle alone."
Are you able to handle him alone? If so, then get the 50/50 time with your son. If she has an issue with it, get a lawyer involved to see what your rights are.
"She do not want to come back and help up at our house too."
That's her right. She doesn't need to help you and likewise you don't need her. Learn everything you can about parenting and children. Become the responsible parent.
Be the man that you want your son to become. Don't live in fear of your W.
But I am working towards reconcile. Does those thing you mention above help?
