|Don't be scared homey.|
That pretty much sums it up.
"What is the necessity of someone weighing 60kg training with someone weighing over 80kgs? Of course, from time to time, yes, but I believe, based on my own experience, that the risk of injuring oneself are well higher than the benefits that this kind of training can bring."
Every time I ever got injured (not hurt, but injured) in training to the extent that I could not train or worse, had long-term damage, it was training with someone north of 25 lb's heavier than me.
The damage to both of my knees, my right shoulder, and the time I tore my oblique, bruised my hip and my kidney,( and when I blew out my knee specifically) all happened training with heavier teammates.