All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger.
It is permissible for a person to ask Allaah to grant him/her martyrdom; rather, it is a recommended act of worship. Sahl Ibn Abi Umaamah Ibn Haneef narrated from his father from his grandfather that the Prophet said: "Whoever sincerely asks Allaah for martyrdom, Allaah Will grant him the status of the martyrs even if he dies in his bed.” [Muslim] Moreover, ‘Umar used to supplicate saying: “O Allaah grant me martyrdom in Your Cause and make my death in the town of your Prophet [i.e. in Al-Madeenah].” [Al-Bukhari] For more benefit, please refer to Fatwa 88367.
As regards Jihaad, it does not necessarily imply that one dies as a martyr, as a man may go out for Jihaad and he returns to his home safely without being killed. Besides, a man may be killed without being a martyr if he did not have a sincere intention in Jihaad. Abu Moosa said: “A man came to the Prophet and said: ''O Allaah's Apostle! What kind of fighting is in Allaah's Cause? (I ask this), for some of us fight because of being enraged and angry and some for the sake of his pride and haughtiness." The Prophet raised his head (as the questioner was standing) and said, "He who fights so that Allaah's Word (Islam) should be the highest, then he fights in Allaah's Cause." [Al-Bukhari] For more benefit on the martyrs of the Hereafter, please refer to Fatwa 83878.
As regards the second part of your question “can he take medical pills to control his anger?”, the answer is that the Prophetic guidance shows us the ways of treating anger, for more benefit on this, please refer to Fatwa 88764 .
Moreover, it is permissible to use the medicines that diminish the effects of anger if this does not lead to any harm; this is a kind of treatment and this is permissible in principle.
Allaah Knows best.