Giving my 3 year old newborn breast milk?

Kingston54

LO 2 is 5 days old and I definitely have an oversupply of breast milk already.

This morning DS, who is 3, woke up with a cold. 100.3 fever, congestion and a little cough. DH suggested maybe I should pump out some breast milk and give it to DS.

Any thoughts on whether this would help or not? We were thinking the breast milk probably has some good antibodies but not sure if it would help a 3 year old...

Thanks!!