If you like to hand embroidery, perhaps prepare some blocks to embroider. Redwork comes to mind. You don't have to switch colors and if you have the pattern already drawn, you can easily pick it up and start sewing. I'd prepare whatever blocks you are doing ahead of time. Then, when you are done with them, sew together into a quilt. I've made at least 6 of the "12 Days of Christmas" wall hangings in redwork......you don't have to pay attention when stitching.
Or, if you like to crochet or knit...take your bag and do some afghans. I've done that before in the hospital, but the balls of yarn can be cumbersome to lug around. I did Project Linus sized afghans and used patterns that utilized many colors (scraps of beauty or a harlequin pattern)...that way I was able to use up that stash.
If you hand-quilt, you could take your round hoop and quilt it (as long as the quilt itself is not huge and cumbersome).
Whatever will keep your hands busy without too much equipment to carry.....and allow you to be interrupted without you losing your place.
Prayers for your father's successful surgery and speedy recovery. Be sure to take care of yourself, rest and drink lots of water.