Can one feed themselves?

Well, "him self" should clearly be "himself," but other than that, in the context of a report on a preschooler, "he fed himself confidently" is perfectly fine. A preschooler who feeds himself well is noteworthy.

Those were the days.

I feed myself. My wife feeds herself. I can feed her. She can feed me. I guess that at this point, and so far, I can and do feed myself with confidence (that I will get everything I want into my mouth without assistance). I am still reasonable neat and can keep most of the meal confined to me and my eating utensils. I hope to be able to continue for some time.

I suppose I could convince some unstable person to put a finger or two into their mouth and to try to eat his or her "self;" but, that would be unseemly and ungrammatical.