Being a landlord is his business. If the bookstore and restaurant lose business and can't pay their rent, he is losing business and potentially can't pay his mortgage on the building.

Being "in it together" means he's giving them time to repay the back rent instead of evicting them if they can't pay, as he legally could. Commercial lease tenants have far fewer rights than residential ones do.

It's easy to spout "rent forgiveness" but where is that money coming from?