Does Allah Almighty’s saying, "And do not throw yourselves with your own hands into destruction," apply to someone who suffers from a disease that worsens with heat and wearing clothes that cover the neck, causing him severe fatigue and hindering his movements, and is he permitted to lighten some of his clothing based on that?

The correct verse is: {And do not throw yourselves with your own hands into destruction}. Its meaning indicates a prohibition against throwing oneself into perdition by abandoning the obligations set by Allah, for abandoning adherence to Allah's law leads to destruction. There is no harm in lightening one's usual clothing in hot weather if the শরعي (Islamic legal) conditions are met, namely that it is thin but does not reveal the skin's color or shape. A woman's neck is 'awrah (private, to be covered). If lightening clothing around the neck leads to a violation of the conditions for শরعي dress, then it is not permissible except out of necessity or dire need, and only to the extent of that necessity. If going out is not necessary, or if it is possible to go out when the heat has subsided, then it is not permissible to go out with lightened clothing.