I wish you peace in this time of sorrow. I am sorry for the loss of your dad.
You have a lot going on now. Your father, comforting your mum, a wedding. All very stressful things to go through. Take care of yourself by taking some time to sit. Quietly by yourself. In the middle of the storm you can find peace.
When faced with this kind of triple whammy of stressful stuff this is what I have done...sat in a comfortable chair, closed my eyes and taken deep breaths. What can I change? And what is going to happen regardless of what I do? What are the most important things.
The wedding will go off regardless. I have always panicked that parties that I have planned somehow won't go off but they do.
Focus on your mum. She will want and need extra support right now.
Your husband? Anyone else to hold his hand right now when he is facing the consequences of drink? Siblings? If not, he is an adult. When I walked into detox last year I was by myself. When I went to rehab it was without my AH. I had a woman I knew take me to both. If he doesn't have a sibling, maybe someone from your local AA office can provide him support IF he wants it. If he doesn't want help to quit the drink and just wants hand holding in his times of trouble I would say give him your sympathy and leave him to his own devices for the time you need to sort the other stuff out.
God bless.