sympathiser vs well-wisher

sympathiser and well-wisher both are nouns.

Word	Noun	Adjective	Verb	Adverb
sympathiser	Yes	No	No	No
well-wisher	Yes	No	No	No

As nouns, sympathiser and well-wisher are synonyms defined as:

sympathiser and well-wisher: someone who shares your feelings or opinions and hopes that you will be successful

Other synonyms of sympathiser include sympathizer.

sympathiser (noun)	well-wisher (noun)
someone who shares your feelings or opinions and hopes that you will be successful	someone who shares your feelings or opinions and hopes that you will be successful
a person who commiserates with someone who has had misfortune