Is it permissible for a husband to fake an illness to obtain early retirement, while knowing he is capable of working?

It is not permissible for your husband to deceive and unlawfully consume people's wealth, based on the Almighty's saying: "O you who have believed, do not consume one another's properties unjustly, but only [in lawful] trade by mutual consent." And based on the saying of the Prophet, peace and blessings be upon him: "Whoever deceives us is not of us," and "Deceit, treachery, and betrayal are in the Hellfire."

Furthermore, a Muslim residing in those lands is obligated to respect their laws that do not contradict Islamic law, as it is a condition for granting residency. Allah has commanded fulfilling contracts, as He, the Almighty, said: "O you who have believed, fulfill [all] contracts." And based on the saying of the Prophet, peace and blessings be upon him: "Muslims are bound by their conditions."

Therefore, it is not permissible for him to deceive them and consume their wealth unjustly. Rather, he must seek lawful sustenance through permissible means, for provisions are decreed, and whoever abandons something for the sake of Allah, Allah will compensate him with something better.