Nuch, My gut feeling is to go ahead and cry, and hold her at the same time. You don't lose strength by breaking down, you're showing the depth of your love with your grief. I imagine your mother knows anyway. And after unloading it, the strength will likely be apparent once again.
I don't cry easily or (until ALS hit) often. I didn't cry when I got the diagnosis, either--neither did my husband. I did cry, however, when I'd struggled with all my strength to climb the stairs as fast as possible, heaving for breath while the phone rang, which ended with my falling onto the floor. Phil ran upstairs as he'd heard me hit and then heard me begin to wail. He laid on top of me and sobbed. It was the kindest thing at that moment he could have done.
We rarely cry now, and usually it's more of a tearing up and quick return to normal. Does your mother ever cry? If so, try joining her. And then learn to laugh together at the crazy, bizarre things which also happen. We actually laugh far more now than ever before, and I consider it my job to make this as much fun for as long as possible. It takes a while to become accustomed to the new realities.
I do understand how very serious it is that you don't have anyone else to help you... and I wonder how you can get some help with this. Do you have any close friends who know what you're doing, who might bring meals, or offer to do errands for you? It really does "take a village" in order to not burn out with fatigue. If anyone offers to help or asks what they can do, have a prepared list of what would really be of use to you. Different folks are comfortable doing different roles.
Blessings,
Ann
p.s. Missy, men are from Mars. I understand what you're going through. If Phil were in my boots (smile), I'd be trying not to cry, knowing it would make him feel even more helpless. And, I would be a basket case, no doubt about it.