You can see what wear and tear will do to hammers over time. This piano has multiple age-related problems, so just changing out hammers would only solve 1 of them problems and may have to be redone if this piano is ever completely rebuilt (action, strings, keytops, soundboard repair, pinblock replacement (possibly repair))
The total job, not including refinishing the case itself, would probably be around $5-6k. It may not be worth it in this case based on the obscure piano brand name, unless there is an emotional connection that would warrant the expenditure. It would be a fun project though!
p.s. Here’s a cool picture I found at the Hobby Lobby. Could make a nice home decor piece!