Mother who does not want to give up the custody of children

Q: I have been searching the net and cant find any lectures on when a mother doesnt want to give up her son to the father. I want us all to reach jannah. Are there any details on the bad effects/punishments on this topic. Are there any books or something reliable I can read on this topic. I am disturbed that my exwife and her husband get more time with my son than me. It is disrupting my sleep and salaat, meaning I loose concentration. I am performing 5 times in masjid and yearn to have my son with me. Society is so corrupt and I desire to teach him the value of islam. Is there any evidence against a step father giving the islamic nurturing over his father. Please any advice or words that I can give them. Islam is strong on liniage, and we will be called by our fathers names, it seems as if they are happy for me to provide minimum teaching as I see my son 2 days a week. Please any lectures or books I could read. Any warnings to mothers who dont wish to give up the right of custody. The wieght of the punishment is on me should my son Allah forbid commit grave sins. What can I do? I get angry and saddened and don't want to loose my character. But anger is from shytaan and I am only human. Please give me some advice.

Returning items not purchased to the seller

Q: Two people are partners in a grocery shop. One is Deeni conscious and the other is not. Hence, it leads to many disputes. One particular dispute is that sometimes, there is an extra product delivered to the shop. One partner wishes to return it and the other wishes to keep it. The Deeni conscious brother keeps quiet in order to maintain the peace. Is this (keeping silent) correct? If not, what should he do for the future? This has happened in the past also where the product was not returned. What should he do to make amends for that?

Is this story authentic?

Q: There is story about a sahabi who went out in path of Allah and prior to leaving said regarding his pregnant wife: i leave what is in the belly of my wife in Allah's care. When he got back he found that his wife had passed away but his child was found living next to the grave. Is this story authentic?

Imaam leading the Salaah with his trousers below his ankles

Q: In the area that I've moved to, the imaam of the local Musjid leads the Salaahs with his trousers below his ankles. Does it diminish from the Musallis reward to follow such an imaam and is it permissible?

Also, after every Salaah, the imaam systematically makes the same short dua after reciting taqdeer once and istigfaar thrice, followed by Ayaatul Kursi, Tasbeeh-e-Fateemi, the fourth kalimaah thrice, and then the same lengthy dua after each Salaah. Is this allowed? And if not, Should I as a Musalli remain in the gathering so as not to create any conflicts with the locals, or rather just leave and perform my Sunnahs?