What is the specific supplication that can be offered for a husband suffering from depression and not praying, so that Allah may guide him to prayer? Are there supplications other than those for dispelling distress, or specific Surahs from the Holy Quran that can be recited with the intention of guiding him and alleviating his severe worries?

A husband who does not pray is a serious problem. The wife should advise him calmly and gently, taking into account his health conditions and choosing suitable times, hoping that Allah may guide him through her. Seeking Allah's help through supplication during times of responsiveness, reciting the Quran to him, especially Al-Fatiha, Al-Ikhlas (definition), and Al-Mu'awwidhatain, can aid in this. She can also try performing Salatul Hajah (definition) (the Prayer of Need) and reciting the supplication mentioned therein, while seeking Allah's assistance, persevering in supplications and remembrances, and fulfilling her obligatory duties.