Think of the emotional support in your marriage as a bank account. You put in a certain amount of energy/love into the account every day. But every day, like clockwork, your husband takes out a massive withdrawal due to his focus on his Family of Origin and their problems. And not only that, he takes that withdrawal and passes it along to his Family of Origin, robbing you of the resources from that account. And the one time you try to make a withdrawal, because you've had a bad day, he pitches a fit because you're not feeding him his daily requirement of support.
If you had a joint checking account, and your husband not only told you that you don't have the right to withdraw from it, but took a large portion of the account and passed it along to his family, would you be OK with that?
His focus on his family is only a symptom of the problem. His unwillingness to share the "spotlight" in the marriage is the problem. It sounds like he MUST be the focus, each and every day, his problems, his worries, his needs. And if you have needs, that's too bad, because he needs you to focus on him again. Marriage is a joint account of love and support. Both partners must be able to take withdrawals, and more importantly, both partners should be willing to make deposits.
When the house is calm and quiet, maybe before bedtime, maybe you should sit down to talk with him about the other day. Tell him that you're sorry he's so stressed about his mother and her illness, but that is a situation that is not likely going to change anytime soon. He can't continue to use it as an excuse to be grumpy or mean to you. You understand that he is worried, but you have emotional needs that must be met too and you have the right to a bad day every once in a while. If he tells you that you don't understand or he can't focus on you when his mother is suffering so, you can tell him that if that is how he feels, he needs to understand when you turn inward/quiet and take care of yourself. If he tells you that you can't do that because he needs your support, ask him when/how/from whom you're supposed to get support.
If he is willing to go to counseling, you should seriously consider it. This is not a situational problem. This is a ingrained "how I treat my spouse" problem.