My Husband Had An Blood Clot In His Lung Last

my husband had an blood clot in his lung last year that nearly killed him , he has to be on blood thinners the rest of his life because of more clots keep forming an they don't know why. he is having bleeding , he said sometimes red sometimes dark red. the doctor said they cant go in and check because of blood thinners . he is now having very bad pain on his right side and having trouble breathing . everytime we go to the hosiptol they say its damage from blood clots . just seems different to him.