I am very sorry that your mom is sick. I sincerely hope she gets better and soon.
Before provide my opinion, please allow me to ask... Have you and your partner been having problems?
How is his personality? Meaning, in the past, how has he responded to emotional situations?
To answer your question: no, of course you are not expecting too much from your partner. But emotional support is a tricky thing. Not everyone can provide it or at least provide it in the we way we would like.
Your mom and your family are on my thoughts.