Leaving Home for a Better Future - Need Advice and Du'a for My Father

Assalamu alaikum. I’m 28 and I moved abroad to try to secure a better future for myself and for my family. Sadly, this year my father was given a terminal diagnosis and the doctors say he likely has only weeks left. My sister is also planning to study abroad for a semester and hopes that will open doors for her overseas too. What’s weighing on me most is my mother. She’s still relatively young at 55, she’s been working her whole life and devoted herself to raising us - it’s just me and my sister. I worry about what will happen to her when my father passes. Of course only Allah knows the future; maybe He will grant different outcomes, but the doctors’ prognosis has been devastating. I’ve taken some time off work and have been spending the last couple of months with my family since the diagnosis, and I plan to stay longer. My anxiety really centers on my mother’s situation. If my sister moves abroad and I marry and can’t return right away, she may be alone. I’m trying to figure out a way to come back home to be closer to her, but realistically I probably can’t do that for a few years. The thought of leaving her alone breaks me and I feel a lot of guilt. Any practical advice, ideas for support, or emotional guidance from fellow Muslims would mean a lot. And please, if you read this, make du'a for my father - may Allah grant him ease, heal him if it is His will, forgive him, and give our family patience and strength. Jazakum Allah khair.