beside, besides

Beside or beside means next to or standing near--
No, put the lamp beside the table.
He stood beside her through the whole ceremony.

Besides or besides means with the means except or with the exception of---
Does anyone besides Dad want anchovies on the pizza?
Besides also means ( informally ) in addition to, or over and above--
We get benefits besides our pay.
It's not far to the store, besides, I'm going that way anyway.

Now that you know that, you can say--
"Will anyone besides my mom stand beside me?

Note--"beside him" means next to him--
She stood beside him throughout the ceremony.
"Besides him" means except for him--
No one noticed, besides him.

Not to be confused with "bedside", meaning at the side of the bed of someone who is sick--
The new doctor has a terrible bedside manner.
She sat at the child's bedside night and day, until he recovered.