Witch Template Problem

Hello,
I am currently in the process of making a mode in which I am making a living entity. To do this, I use a witch template. But I have a problem;
As I wanted, the entity drinks a healing potion when it thinks it needs it, but after using it, the iron sword that was previously in its hand is gone forever.

I would like either the entity to drink the potion with the left hand so as not to take the right hand slot where there is the sword, or the sword to reappear after using the potion.

If this involves code, please offer me examples or tutorials.

Thank you for your help.