Is a wife permitted to refuse her husband's bed if he is neglectful of prayer due to ceremonial impurity (janabah)? And would she be sinful if she refused? What should she do?

It is impermissible for a Muslim to intentionally delay performing the ghusl (definition) (ritual bath) after janabah (definition) (state of ritual impurity requiring ghusl) until the time for prayer expires. This is because negligence in performing prayer and delaying it beyond its prescribed time without a valid excuse is a major sin. It is advised to explain the seriousness of abandoning prayer to the husband, seek help from righteous people, and persevere in offering him advice and supplicating for his guidance. However, a wife's refusal to share the marital bed is neither a solution nor permissible. If the husband insists on abandoning prayer after janabah, there is no good in remaining with him, and she should not allow him access to herself until he repents to Allah and resolves to perform prayers at their appointed times.