I think looking at used is definitely the way to go. Perhaps an integrated amp from NAD,Cambridge Audio,or Marantz with a MM phono stage built in. There are a ton of lower priced speakers on the market,Elac,PSB,Paradigm,just for an example. Turntables,ProJect makes some decent lower price offerings. There are more. Some folks might recommend vintage,which is fine. But remember,eventually old stuff wears out.
It’s wonderful thing you and your sister are doing for your dad. Kudos to you!