Washing machines can be hard on bra hooks.
The hooks tend to catch onto other clothing and then bend. I've tried putting bras in a mesh laundry bag—ideal for stockings or lacy panties. I tried making a point of folding the ends into the cups. But no, the bras keep on hooking onto other clothes.
My solution for a perfectly good daily-ware bra with one or more kooks missing—rendering the bra useless—is to keep replacement hooks in my sewing kit.
When the unfortunate happens, I remove the broken hook by opening the end of the bra's fastening strap just enough to get the broken hook out and insert a new hook—small jewellery-making pliers works well to pull the broken hook or bits of hooks out (it is important to remove all the pieces, a leftover piece of hook become most uncomfortable when wearing the bra). I then sew the new hook into position and sew up the opening. Voila, good for use again!
Tip: do not wash your (her) special lingerie in the washing mashing, rather let them soak a little in a bowl with lukewarm water and detergent, and wash them gently by hand. Alternatively wash them on a gentle washing machine cycle with other delicates. (You will be in big trouble if her delicate lingerie is spoiled). Do not hang the delicates on the washing line either, let them dry on a towel.
When looking for pictures to illustrate this post I came across something I've never seen, which is such a wonderful idea: armpit snap shields. Visit the URL for more information on disposable and washable armpit shield—they absorb sweat, keep the individual comfortable, as well as save time and money on dry-cleaning.