The best thing to do is patch the hole. I simply use fabric glue and some pieces of blue jeans that you probably have hanging around. Trim off the extra threads and then apply fabric glue to the back of the waist band covering the hole made by the old button. Do the same on the front and then let dry. about 30 minutes or so, if you have a machine I always stitch back and for on the edges. Trim any edges or use additional glue to tack them down. Now because you have strengthened the hole carefully push the back of the button through where you can see the end, add the front to the nail end and turning the garment face down on a protected hard surface hammer about 3 times and check to see if it is sturdy, continue to hammer until you have reached the objective. Now you have got many more years with that button.