You are wonderful to help,this man and his matted Yorkie
I am not familiar with either if the lotions you mentioned - may have different names here in the States, but it sounds like you have the correct idea.
Please let us know how it goes. That poor pup was traumatized by the groomer and you are correct that it may need to be sedated so it will not be so traumatic for it.
I do hope you will keep us posted!