Based on what you have said, and unless she has other assets solely in her name, the answer is likely to be - no.
Joint marital property means either party can use the property.
However if there are remaining assets in your son's name, he should make sure they stay in his name and keep as many records and evidence of the gambling losses as he can because those losses may be able to be used to say your son should keep 100% of the remaining property.