It's not the most direct patient care but I'd argue yes. You're with patients, you're in a definitive clinical environment, and you're doing something meaningful for them (even though you aren't providing physical healthcare).
I should also say it might dependent a bit on how you spin it...if you're just performing in front of the nurses I'd give it a little less weight, but if you're going into patient rooms to perform then I'd give that a little more weight.
You are in a clinical setting (so technically you can), but giving you insight on the doctor-patient relationship will require more direct observation.
Yeah, volunteering as a musician in the ICU totally counts as clinical experience! Even though it’s not the typical hands-on medical stuff, you’re still in a healthcare setting, interacting with patients and their families