A stock bumper is a worthless anchor point, so with a receiver mount winch the only anchor point is the winch mount. Single line the winch will stall before you exceed the receiver capacity, assuming an 8 or 9,000lb winch. So you can easily exceed the capacity of such a mount with a double line pull.
Will you always do it? No, but you have no way to know if you are or not with a double line pull.

I wasn't talking about a homemade receiver mount, I was talking about a homemade winch bumper. Given the equipment his friend has, I'm sure he could help him build a bumper that wouldn't bend.
If he can't, he can use the photos and dimensions in this thread to build one that he won't bend.
https://www.ford-trucks.com/forums/1...on-needed.html