The last wish of testator narrated in last valid WILL is supreme.
The Lady can make a WILL that after death her property (mentioned and bequeathed in WILL) can be enjoyed by her husband (without any right to dispose/alienate/sell/ gift etc etc) and after her husband the property shall devolve to her son…………………..
She can narrate what her son can do with her property…. Enjoy or enjoy and dispose also……
No she cannot make such a will , if she wants to give her property to her son after the death of her husband then she can make the will in favour of her son and give enjoyment right to her husband in that property till her husband death .