Old man needs your help

My Issue has to be primitive to you experts.

I’m an 82 year old novice dependent on my Adobe InDesign CS4.

During my training material design & development years we stated with PageMaker 4,

then PageMaker 6, then 7, then CS2, then CS4. I have dozends of valuable docs,

that I no longer can access and manipulate due to my current OS 10.13.6 High Sierra.

I need a temporary solution, but can’t afford, nor need a new suite of programs.

Of course I’m long retired, but putter and am in the process of developing one more final program - 

‘What I wasn’t taught in school, but should have been’.

How can I still use my CS4? Or, what other desktop publishing program opens and allows me to modify CS4 docs?

Thank you ever so much. Please respond to [Personal information removed by moderator.]

as I don't understand these 'communities' There are an overwhelming number of options - too confusing.

Thank you for your help.