you have to do what is right for your family, but i just want to give you a heads up on a few issues to take into consideration. i'm saying this as a non elderly person, but one who is retired and moved from one state to another.
1. look to how the move will impact their income. if they get a pension from an illinois entity it might be subject to double state taxing. they might have to pay state tax every year to both illinois and california (and dang, california has high state tax rates-one of the reasons we moved).
2. if they have private insurance as a retiree benefit see if it even offers out of state coverage, and if it does how much it costs.
my former employer was required by law to provide a plan to out of state retirees-i pay 250% more of a monthly premium, for a much lower coverage plan than my fellow retirees from that same employer that live in the state i retired from.
3. if the coverage extends to california DO NOT TRUST the insurance company's list of supposed providers. call them individualy to see if (1) they are still contracted with the company, (2) if they are even taking patients. this is a HUGE issue with us right now, the number of providers has been cut back so drasticly that we are forced to use non contracted which means huge out of pocket expenses.
4. if they have medicare make sure that there are medicare doctors in the area they will live that are even accepting new patients. some doctors don't have a wait list, some may have a 2 year anticipated wait. with a person with existing health care issues this can pose major problems. if they have a medicaid type insurance they will have to file an application for mediCAL in california-it does not transfer like medicare. the eligibiltiy criteria is different from state to state, and a person eligible in one state may not be in another (i administered this program in california-we did have elderly people move in with kids only to find out the benefits they were eligible to in another state they had no eligibility to in california

)
5. if they have existing wills/trusts check what will need to be changed with the california move, and get anything that needs to be done in the other state taken care of before the move.
we learned about this b/c dh's mom was considering a move to another state. what is an acceptable or executable will in one state may not be in another. what is an acceptable poa in one state may not be in another. one state may have one kind of probate/executing requirement, the state the person lived in may have another. they can conflict and create large expenses to try to execute even at the simplest level.
on medical records we found that we could have them sent to new providers OR if the original provider was techno smart and kept their records on a data base-they transferred them to US, and we could provide a copy to the new doctors (then if doctors changed we could quickly provide the new ones with the info).
on moving expenses-i agree with others that depending on the items it might be less expensive to buy replacements. electronics, depending on the age can be more expensive to move than replace. same with furniture (the exception would be medical equipment that an insurance paid for a portion of and the person is'nt eligible to getting another kick in of the costs-this was the situation w/ my mom's recliner that has a seat lift in it).