I doubt he will use it without his grandmothers permission..
But as someone said before, you dont want it affecting the old girls benefit entitlements. Let her rest peacefully, last thing you need is her talking to a jackass paypal employer on the phone all day and getting no result (a bit like us)....
Honestly imo you can use her social. For gods sake she is 90. Stay under 200 items and 20,000 dollars. Only proceed if you know stealth. If not then no.
__________________
I'm a hustler's hope, I'm not his pipe dreams.