Can I negotiate my husband's total student loan amount?

My husband is unable to work due to chronic Lyme disease and many symptoms. I currently have a strong salary, but it is difficult to consider paying his student loans on only my paycheck alone. It would cost about $600 a month (about $70,000 total), which seems like so much since he cannot even work. This is about the same as our mortgage payment (before escrow and PMI).

Last month, he told them that he is unemployed, and they said that he could apply to not pay right now, but he would still be accruing interest. It doesn't seem likely that he will have a full-time job within the next year or more while he gets treatment for severe medical symptoms, so I'm not sure that this is a good idea.

When he was working, he was working as a social worker (essentially), not a doctor. I wish he didn't have such high loans for such a low-paying field. The $600 a month for the next decade or two seems doable but would really lower our capability to adopt a child, travel -- anything, really. I'm almost 30, and he is in his late 30s. I appreciate any advice.

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