Can a person combine prayers without shortening if she is sick and if she feels her sickness might become worse later on in the night and also because she may sleep off due to tiredness from her illness.
You are not allowed to combine maghrib with isha except if there is a necessity.
In case of sickness, then it will be a temporary state, if the person really is not able to pray each prayer at its correct time, as soon as he is able, he needs to pray them separately at their timing.
Allah said that prayers are according to set times.
And one of the conditions of prayers is that the time of each salah has to be “entered” or reached (دخول الوقت)