I`m a god-fearing woman. I`m two months pregnant but my husband insists that I have an abortion?

What is the ruling on singing and listening to it while accompanied and unaccompanied by musical instruments?

Singing and listening to it unaccompanied by musical instruments is permissible as long as it isn`t practiced as a profession and is done by a man to other men, or a woman to other women with maintaining that no temptations are involved. The words of the song should be Islamic, and if temptation was likely to happen, then the singing becomes definitely forbidden. Temptation here means: whatever leads to committing a sin. In Islamic Sharia, singing accompanied by musical instruments such as the lute and the like is forbidden, and listening to it as well. The reason behind that is the fact that the musical instrument itself is forbidden. However, striking the tambourine and singing Islamic songs are permissible in weddings, circumcisions and the like.

Is it permissible for a woman to sit with her brothers –in- law?

It is impermissible for a woman to sit with her brothers-in-law, and it is also impermissible for a person to have a Khulwa(seclusion) with his sister-in-law.

Is it permissible for the woman to use her mobile phone while on the street?

All Perfect Praise is due to Allah, The Lord of The Worlds 

Modesty should be observed by the woman at all times, so she is free to use her phone while on the street as long as it is done within the limits of Islamic manners. And Allah The Almigty Knows Best.