Only one thing for it, if he wants to live:

Get the =FUCK= off of all animal "foods". =NOW=. It's animal fats from =all= animal not-foods, including all dairy and eggs, that are clogging him up. Plant fats and oils will also "clog his pipes", but not as bad.

Here is one of the best how-to's that I know of: https://veganuary.com/en-us/

Just 'cause it looks like "January" does not mean wait.

He does not have -time- to wait.

Start =now=. Continue forever.

Do the program with him. Support and encourage each other. If you try something new - share. If one of you doesn't like it, maybe the other will.

Me? My Seventeenth "veganniversary" is in March. I'll be 71. I switched at age 54.
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Oh - and I gotta tell ya -Open Heart Surgery sucks big time.
So does being asked if you want a DNR order - Do Not Resuscitate. I told them to keep jump starting me until I was charcoal.
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Also, another how-to: https://www.pcrm.org/vegankickstart
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Both programs are =Free=. Nada. Zilch. You pay them =Nothing=.
Except, ya gotta buy food. But, ya gotta buy food anyways. Just buy =food=. Don't buy the not-'foods' that will =kill= you.

Lotsa people find their food budget goes down.
My budget runs $47-57 USD/week. ("Funny" numbers because I just subtracted out what I donate to my Humanist group.)
If you go with a lot of the 'replacements' for meats and cheeses, yeah, then maybe goes up.

Questions? I've been around long enough that I can probably answer them.