It sounds as though you need to confide in a good friend who stays near you and has preferably met him in the past who could help if you felt threatened in any way in the future. By all means get someone to check he's not lying ill in his house or in hospital. If it was drink speaking - well, you certainly don't want to take that on again. Maybe someone else he knows could encourage him to get help, including perhaps going walking with a group. If he's in the early stages of dementia or has some other illness, hopefully he'll get support but you would have to think very carefully about staying in touch - it might not be wise and you could be drawn into some sort of care giving role with someone who could go on to say more distressing things or even start touching you inappropriately.
If he's fancied you for a while but simply didn't know how to articulate it, then poured it all out at once, I think it still sounds highly inappropriate. In that case ,I would be inclined not to stay in touch as he might not be happy with a platonic relationship and you probably wouldn't be comfortable in his company again. Not intending to be alarmist, but is there any chance he would engage in stalker - like activity? Maybe have a word you can use in a phone call to a nearby friend or neighbour if he turns up and harasses you, so they can check you're ok.
Whatever is behind it, looks like the friendship is probably over.