"We should cherish/visit our mothers/grandmothers as much as possible because you never know when it's their time."
He also retweeted a quote from Mufti Ismail Menk, a muslim cleric, just after news of her loss broke.
"When we suffer a loss, we become sad. We lose hope. We forget that He rewards us for the patience & endurance, way beyond what we've lost."
The All Blacks star shared an incredibly special connection to his grandmother and has made sure he's always been there when she was facing battles with her health.
After the 2011 Rugby World Cup missed all three of the All Black victory parades after his Auckland-based grandmother was admitted to hospital with an undisclosed condition.
"You only have one family," a source close to Williams said at the time. "Celebrating and thanking fans can be made any time."
In March, Sonny Bill Williams shared these beautiful photos of them together as he took time off from his All Blacks sevens duties because of a knee injury.