1) your husband as father is bound to maintain his son .
2) if he refuses to shoulder financial responsibilities make an application for maintenance of the child before the family court
3) your husband can be directed by court to pay 1/3rd of his income as maintenance .
4) if husband does not want to take child abroad dont apply for Tc
5) make it clear to your son that you have no objection for his migrating abroad with father but your father is the one who has raised roadblocks in issue of TC
6) you can also apply for divorce and seek alimony and other reliefs from your husband