According to the Congregation for the Doctrine of the Faith, Arturo Sosa is no in full communion with the Catholic Church.
2. Furthermore, each and everything set forth definitively by the Magisterium of the Church regarding teaching on faith and morals must be firmly accepted and held; namely, those things required for the holy keeping and faithful exposition of the deposit of faith; therefore, anyone who rejects propositions which are to be held definitively sets himself against the teaching of the Catholic Church.15 Whoever denies these truths would be in a position of rejecting a truth of Catholic doctrine16 and would therefore no longer be in full communion with the Catholic Church.
Canon 1436
1. Whoever denies a truth which must be believed with divine and catholic faith, or who calls into doubt, or who totally repudiates the Christian faith, and does not retract after having been legitimately warned, is to be punished as a heretic or an apostate with a major excommunication; a cleric moreover can be punished with other penalties, not excluding deposition.
[8] Codex Canonum Ecclesiarum Orientalium, can. 1436 - § 1. Qui aliquam veritatem fide divina et catholica credendam denegat vel eam in dubium ponit aut fidem christianam ex toto repudiat et legitime monitus non resipiscit, ut haereticus aut apostata excommunicatione maiore puniatur, clericus praeterea aliis poenis puniri potest non exclusa depositione.