How many {sibling} are to/by {Thor} ?
Thor, how many brothers?
SELECT (COUNT(?sub) AS ?value ) { ?sub wdt:P3373 wd:Q42952 }
SELECT (COUNT(?sub) AS ?subs ) {
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#subject> ?sub .
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#predicate> <http://www.wikidata.org/entity/P3373> .
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#object> http://wikidata.dbpedia.org/resource/Q42952 .
} 

Which is the number of brothers that Thor have?