Looking on how to approach a Cluttered Rental House

[Andrew Trevino]

So, looking for any advice. 

I recently inherited a rental house from a family member. The tenant has been in the house for over two years and paid every 1st of the month (The house is slightly under market rent) and has never been late on rent. The renter is an older gentleman (in his late 60s) and has stated that he does not plan to move. I went to conduct a minor repair and when I went inside the house, I noticed that there was a ton of clutter inside. I think since the man is older, he has some hoarder tendencies. I've brought it to his attention recently. If nothing changes, how would yall approach this scenario?  I'm conflicted since he's been paying on time for an extended period.