In the Name of Allah, Most Gracious, Most Merciful.
All praise and thanks are due to Allah, and peace and blessings be upon His Messenger.
In this fatwa:
Yes, you can borrow money from your son to pay your zakah as long as you believe you are able to pay it back.
In his response to your question, Prof. Dr. Monzer Kahf, Professor of Islamic Finance and Economics at Qatar Faculty of Islamic Studies, states:
Yes, you can borrow money from your son to pay your zakah as long as you believe you are able to pay it back
In fact, it is better to do that because delaying the payment of zakah with ability to pay through this means is not permissible.
Almighty Allah knows best.