All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad, sallallaahu ‘alayhi wa sallam, is His Slave and Messenger.
The husband is Islamically ordered to treat his wife in a kind manner as we have pointed out in Fataawa 86618 and 88304. If your husband as you stated treats you harshly, disdains you and insults you, then he is very wrong. Rather, good treatment should prevail between the couple and their in-laws and thus the husband should respect his wives' parents and family and not insult them and they should respect him. Similarly, the wife should respect her in-laws and they should respect her and not mistreat her.
The most important thing we advise you to do is to observe patience and supplicate Allaah The Almighty to reform your husband and his family and guide them to what is right because Du‘aa’ (supplicating Allaah The Almighty) is the weapon of the believer. That is better than supplicating Allaah The Almighty against them. Although the supplication of the oppressed against his oppressor is allowed without transgressing the limits, the fact remains that pardoning is better and of greater reward as explained in Fataawa 130288 and 84351.
Also, you should seek the help of some righteous and wise people to reach reconciliation between you and them. If the matter is settled, it is good for you and your husband. But if the matter remains as it is, then you have the right to seek divorce for harm. Divorce is sometimes better while in some other times observing patience may be better, according to the different circumstances. Ibn Qudaamah said in Al-Mughni: “Conditions may get worse between the husband and his wife and thus staying married will become a total corruption and harm by just obligating the husband to spend and accommodate his wife, and keeping her in his house subjected to bad treatment and continuous dispute to no avail. This entailed prescribing what ends marriage so that the harm caused may be removed.” [End quote]
So, try to balance between the benefit of staying married to him and the benefit of taking divorce from him, and seek the advice of righteous people regarding that.
If divorce takes place, then the right of custody of the child is given to the mother so long as she does not remarry as was previously explained in Fatwa 89832. This applies if the two spouses live in the same country, but if one of them wants to move to another country, then there are different opinions regarding the one who is more entitled to the custody in that case. Anyway, the interests of the child should be observed. In most cases, it is better for him to remain with his mother. If a dispute occurs, then the authorities that are authorized to look into the cases of Muslims such as the Islamic Centers are to settle that matter, and thus the case should be referred to them.
As for what your husband told your mother that he would send you to see them once every year, it is a promise that should be honored as far as possible. However, it is not permissible for you to travel without a Mahram, even if your husband allowed you to travel. For more benefit, kindly refer to Fatwa 83795. Indeed, means of communicating with one’s family have become available nowadays such as phones and the other different means of communication on which you can see your family and they can see you.
As regards immunizing the baby, then it is not generally obligatory upon the man (father); however, this is to be decided by custom; so if the custom is that the woman (mother) is the one who does that, then she will be obligated to do it and if the custom is that the woman has nothing to do with that, then the man will be obligated to do it.
For more benefit, please refer to Fatwa 181485.
Allaah Knows best.