Why do you want to go and how far gone is he?
When my dad first went into a care home with dementia, he often did not recognise me, though occasionally would, but still seemed to derive some pleasure from having a visitor.
Later, he was so completely out of it, he wasn't really aware that he had visitors at all.
If I hadn't been visiting weekly and so seeing his decline, I would have been shocked and distressed to see him in the later stages, emaciated, agitated, nothing like the man he had been. But just occasionally, there might be a moment when we made eye contact or he allowed me to hold his hand (mostly he wouldn't) when I felt we'd had some genuine contact.
I actually wanted to protect him from occasional visitors. I didn't want them to see what he had been reduced to. He was such a proud man, so dignified, socially reserved. He would have hated people to have seen him in bed in his incontinence pants, with all his dignity and privacy stolen from him.
If there is something that you can do for him, if it will make a difference to him, then visit. If it's too late, I wouldn't bother - better to remember him as he was.