Is it permissible for a bedridden patient to combine and shorten prayers and perform tayammum for them?

Islam permits the sick person to pray while sitting. If unable, then while lying down, gesturing for bowing (ruku') and prostration (sujud), based on the hadith of Imran ibn Husayn. It is permissible for a sick person to combine two prayers, either by advancing or delaying them, if performing each prayer at its appointed time causes him hardship. However, shortening the prayer (qasr) is not permissible for the sick. It is permissible for the sick person to perform tayammum (dry ablution) if using water would harm him or delay his recovery, or if he is unable to use water and fears the time for the prayer will elapse.