I think that before I answer this, I should point out that we don't advise on specific cases and it is always best to get face-to-face advice on your individual situation.
However, in principle, it is entirely possible to get DLA whilst working, and indeed many people do.
If your husband starts working, he should notify the DWP of the fact that he is starting work and whether there are any changes to his care and/or mobility needs.
I am moving this thread to the benefits questions forum.