Q:  What did Jesus mean when He said that the servant would be “cut asunder” and “appoint[ed] him his portion with the hypocrites,” where there is “weeping and gnashing of teeth”?

A: This parable is not too easy to interpret, but this is how I understand it: The servants are leaders or rulers in Israel, and the evil servant represents those who are not looking for Christ’s (the Messiah) return, and are living in evilly. Consequently, when Christ returns to the earth, He finds certain evil servants, (not being wise and faithful and ruling Christ’s household well), and “cuts them asunder,” or kills them. 

Concerning "his portion being appointed with the hypocrites”:  Since the evil servant(s) belong to one of the 12 tribes of Israel who in the Millennial Kingdom will each have their portion of land, as described in Ezekiel 48. The evil servant is killed and his portion is appointed with the hypocrites, who, also, will have no portion in the kingdom. 

Thus, nether the evil servant(s) nor his family will gain any portion of the land which the 12 tribes will inherit in the coming kingdom. And all the hypocrites, who will have no part of Israel’s glory and blessings, will bitterly be “weeping and gnashing their teeth.”