It is possible but not recommended. You will loose tons of performance plus can't take advantage of the integrated security.
If you worry about nodes going down, just cluster your JBoss/Tomcat nodes. We do provide clustering with Tomcat. This way you don't waste your time serializing calls between two processes and can use the integrated security manager between tomcat and JBoss. Plus you only have one server configuration to manage/maintain/test rather than fucking around with tomcat config separate from JBoss config.
In short, your PHB is clueless. Use integrated servlet/ejb container and cluster for failover.