Wondering: good question! Rebbe Nachman of Breslov, and modern Breslovers, teach that everyone should pray at least an hour a day of personal prayers in his/her own language, including thanking Hashem, examining one’s deeds and doing teshuvah for them, and asking Hashem for whatever we need physically or spiritually. Rav Shalom Arush, in his book In Forest Fields (which I highly recommend), says that one should devote half of one’s personal prayers (hitbodedut) each day to the one big thing that you need (in his examples, often this is overcoming a particular negative character trait or tendency to sin in a certain way). If the thing that is concerning you most is the refua for this person, perhaps you could devote a fixed amount of time each day, perhaps at least 30 minutes per Rav Arush’s teaching. Rav Arush also discusses in that book the concept of a six-hour prayer session when a major salvation is needed. Rav Moshe Erez Doron has also written quite a bit about personal prayer that is worth reading. For example, in Make Every Word Count he addresses the question of whether Hashem can get “bored” with our “repetitive prayers.” The answer: no! Rav Arush also addresses similar questions.
People see Breslov practices and advice and think they’re only for the Breslovers, but the truth is many non-Chassidic rabbis throughout the ages have had similar advice, to spend much time in personal prayer. And more recent non-Chassidic rabbis have also learned from Rebbe Nachman’s teachings. For example, Rabbi Eliyahu Dessler encouraged his children to read Rebbe Nachman’s works, and the Baba Sali and at least some of his sons learned Breslov works and gave them as gifts to their children.