Sorry, long answer...
Does he already have employees he trusts? Could one of them sit in on interviews and give an opinion afterwards?
Is there any chance that his/your collective decision is skewed towards people who are attractive and well-presented but who have no "depth"? Are references being checked properly?
Is he/are you covertly discriminating, for example, against older or disabled people who may have long, steady work records and a wealth of relevant experience?
Is the pay at a fair level, commensurate with the duties etc rather than, say, minimum wage (the least that an employer can legally get away with)? Is the work being accurately presented during the application process? Is it possible that employees are starting work only to find the job is not what they anticipated and that they are expected to take on big responsibilities for little reward?
Turning full responsibility over to an employee may simply not be appropriate - it is DH's business so he needs to be aware of what is going on at all times. Has he contemplated having a business partner (I realise this may simply not be possible financially or otherwise)?
Hard for you/him to be objective but is he a fair, approachable, boss or does he, for example, take it amiss when employees ask for time to go for dental/medical appointments?
Is the process being hurried without proper consideration?
Are employees properly trained? Are they listened to/consulted? An excellent candidate may lack one core skill which can be acquired on the job.
Don't just look out at potential employees, look inwardly to see what is offered and expected. How are the physical working conditions? Are safety requirements adhered to?
Perhaps an applicant's outside interests give a clue to abilities/organisation etc. Ask what he/she would do in X situation, ask for an account of when he/she demonstrated abilities required in the job on offer.
(Sorry for the essay, am currently job hunting. At my last interview I spoke to the tops of two heads while the interviewers scribbled all I said in longhand!!)