I was convicted of fraud. It is an offence with intent. Mine was also a family member and yes, I went to prison. This was 7 years ago.
Your husband is covering for him. Your son is lying and cheating his family. You don't have to throw him out. However, it needs reporting and he needs to accept the consequences of his actions.
Believe me, when I has nobody left to lie to, steAl from, did I develop a conscience and grasp that I had no right to do the things I did nor hurt my family in the way I did.
It's awful for you, but stop it now, and let him accept what's coming to him.
Since prison, I set up an organisation. Not the best thing that's happened to me, but it taught me the harsh lesson I needed.
In the Crime section, there's a thread called 'What to take to prison 2' a mother who's daughter has been in prison often. The mother is amazing in how she supports her daughter. You'll find lots of support there.
And happy to advise you on actions you should take now. Take the card and let the company know that it is being used without your permission.
Best of luck.