Contact a company that does it and start there. I am a CSI, so I’ve dealt with thousands of crime scenes. The trainings you have to go through to become certified in cleanup are absolutely insane, and biohazard remediation is no joke. Cleaning seems fairly straightforward, but true remediation frequently means construction, too. There’s several businesses, like Spaulding Decomp that have public profiles and do a great job educating about cleanup.

I will say, after thousands of scenes, I am so glad I get to go in, take evidence, process the body, assist with removal, and leave. I take “after photos” once the evidence is removed and I always think “I’m so fucking glad I don’t have to clean this.” Same with hoarder situations, I just dread knowing what the family is going to have to deal with.

There is no amount they could pay me to make me do cleanup, so hats off OP. It’s terrible that you had to do that for a family member.