SUggestion
1. Mom moves all the funds to some other safe place immediately BEFORE asking any questions, lest somebody freeze the account until any smoke clears .
2: Somebody makes a police report and has a copy of same as to the ransacked premises.
3. IF Mom wants role of administrator under intestacy she moves that ball forward promptly ...and retains counsel as she sees fit....may well NOT be one she contacted earlier. PErhaps, IF the named executor in the invalid will is reliable,in Moms opinion, she jawbones that person to step up to plate ...the intestacy law may provide a priority of applicants and a time frame , look it up.
4. Mom keeps very accurate records, receipts of everything she expended to safeguard the estate including time records ...