If a check cashing company did cash the check without the endorsement of all payees, your insurance company would almost certainly refuse payment of the check due to "Missing endorsement" When this occurs the check is returned to the check cashing company unpaid. At that point the check cashing company would come after you to get their money back, taking you to court if needed. Your options are working through your insurance comapny and getting the check reissued in your name only or using FedEX, DHL, UPS, etc sending the check to your mom to sign, and having her send it back to you.
The second way does not guarantee your bank will accept it as they may wish to verify your mother's identification before accepting it for deposit or cash.
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I can do all things through Him who gives me strength. (Phillipians 4:13)