Is it permissible to perform tayammum for Fajr prayer due to fear of revealing one's conversion to Islam to family members who hate Islam?

This woman is not permitted to substitute tayammum (definition) for water, as water is available and she is able to use it. Her fear that her family might discover her situation due to incomplete ablution is insufficient. She can perform ablution quietly. The mere fact that she wakes up for Fajr prayer daily might reveal her situation, yet she is not permitted to abandon prayer. Faith is a test and a trial, and she must accustom herself to this and be patient; she will find a good outcome. We advise Muslim women to provide care and counsel to her, and not to leave her to face these problems alone.