Just My 2 Cents ;0)
I just went back to reread your original post...LOL...and you weren't asking anything about preservatives directly. More along the lines of needing an easy tallow lotion recipe. Sorry I got so off topic!
I have Lard, but not beef fat. But not sure how one might differ from the other in lotion.
Tabitha gave some good advice about the body butter, since you don't have a preservative.
A lotion may be best for the face, as to not clog pores. But even in the fridge it may go bad in a week or so. TT and refrigeration combined would definitely slow that process down. But not near as long as a traditional preservative would.
Onto the next subject...LOL...Shea butter is very rich and moisturizing, as you mentioned needing for him. I use my body butter for severe dry places and it does the ob, when lotion doesn't quite cut it.
I whipped some shea butter with jojoba oil recently. Melted the shea butter down and whipped it with the oil, until it came back to room tempature. I then stopped whipping when I got the consistency of whipped butter I wanted, and gently (trying not to pack it a that defeats the purpose of whipping) put it in a wide mouth jar. If you don't have any, Wal-Mart usually has some cheap ones in the toiletry section, with the other travel size products. I didn't need water, and thus didn't need a preservative. Plus Shea tends to naturally preserve on it's own. Jojoba is really good at not going rancid too quick, as well.
You could also do a lotion (if you refrigerate) WITH Shea. Melt the she butter down to an oil and make your lotion as normal. I have a shea butter lotion. It too is very moisturizing, more so than a basic lotion may be.
I would test out a whipped body butter with shea and lard or a lard lotion and let you know how it does on mine and my mother's eczema type condition. But I have no shea butter to melt down and whip with lard (for body butter) and no emulsifying wax to keep the lard and water together (for a lotion).
I plan to make an order for both to continue making my products.
If I get them in the mail, before you make it...I'll post my results.
But that'll probably be a week or so. And you probably need results quicker than that.
Sorry I couldn't be of more help.