grandtanteJE65, for many years, I have worked in Industrial safety, and the symptoms/behaviour your husband is exhibiting is not unusual for any person (man or woman) following a severe accident.
In cases such as described, it is often the psychological fear of a similar incident occurring that makes a person withdraw from any activity that could bring about any such circumstance again. In such a contingency remedial action typically includes both physiotherapy on the limbs or other parts of the body affected by the incident, and psychological therapy carried out by professional persons.
The above in almost all cases bring about an outcome that allows the affected person to resume a normal healthy life (or as near normal as any chronic physical injury will allow). However, in the vast majority of cases, we deal with, there is the incentive within the person affected by the accident to return to work, which is often well supported by an employer.
In such circumstances should the person who incurred the injury not fully comply with the remedial action recommended, then that person can face disciplinary action by the employer which can lead to dismissal from his or her employment. The forgoing make for a strong incentive to comply as loss of any social security benefits can the result from non-compliance, and a reduction in the financial amount eventually paid of any claim the person may have against the employer
The reason I point out the above grandtanteJE65, is that I feel you have to bring similar pressures to bear on your husband if he is to return to having a full healthy life. You do not state if he was working at the time of the accident, but I am assuming he was not. Therefore to seek outside professional advice by way of your GP could be a first step, as the lifestyle, he is now living will in time (in all probability) bring about other medical issues.
Hope this helps.