What response can I give my husband when he asks to reactivate his cell phone?

If his phone is blue tooth capable he can look into getting a neck loop that will connect wirelessly to the aids.

There is always the possibility that his phone is already considered "out of date" & he'll have to get a updated phone (which is how the companies make money as they will tell you they no longer have batteries that fit it - this happened to me).
If you husband is out & about sure, get him a phone. Or you can always get one from Walmart where you pay for data as you go.
Absolutely have his ears checked for wax buildup. PCP's clean ears as well. 

Cwillie, we think alike....the best thing about a cell phone is you can text. All of my dear friends use smart phones because they only text.

Can he text?

Google " cell phones for hearing impaired". I just did and a whole bunch of options came up.

Talk to your cell phone provider about his deafness, they may have a model that can help him. Also try to get him to an ENT to check his ears for wax buildup. My husband walked around for two years thinking he was deaf in his right ear. It was all waxy.