Assalamu alaikum Ustadh. Can one read that book The remembrance of death and the afterlife by Imam ibn Qudamah or other books by the imam?

Take ilm level by level and yes you can read for ibn qudamah what is suitable for u like umdat al fiqh for example in hanbali fiqh or lum'at al itiqah woth an explanation it is better ofcourse.