Well I hope it works out for the horse. I know how it feels when you want the assurance of a "competant vet". Last time I called a vet out on emergency, my friend and vet was out of town...wow, what a panicked and sinking feeling, that was! It all worked out, as in she was fine before the vet arrived (yeah, that and a few bucks later). So, I feel for your friend.
Timothy goes for a premium everywhere, I think. Beautiful to look at, ain't it? But, its sugar content can fluctuate between cuttings depending on conditions (and here they don't get many cuttings b/c it is grown at higher altitude). I would not feed clover. We never included it when we re- seed our horse pastures (when we had pastures)...even though it is great for your soil. Dry or in pasture, the stuff just scares me.
That is why alfalfa is a good bet - something like the 1st cut of a mature stand (not new planting) b/c it is stemmy w/o all the leaf he doesn't need just standing around. This may not be available, but alfalfa cubes may be.