I just wanted to ask if it is okay to pray after sunrise someone I know has 5 kids and they trouble her so she gets tired and prays fajr after sunrise willl allah forgive her if she dies upon this or will she go to jahannam.
The matter is not that simple:
As it was said in the comments the prayer is a due on every Muslim and Muslima. Praying on time is also a due on every Muslim and Muslima:
... Indeed, prayer has been decreed upon the believers a decree of specified times. (4:103)
However the sunnah gives us a bit ease:
The Prophet (ﷺ) said, "If anyone forgets a prayer he should pray that prayer when he remembers it. There is no expiation except to pray the same." Then he recited: "Establish prayer for My (i.e. Allah's) remembrance." (20.14). (Sahih al-Bukhari)
When any one of you omits the prayer due to sleep or he forgets it, he should observe it when he remembers it, for Allah has said:" Observe prayer for remembrance of Me." (Sahih Muslim)
The above ahadith give valid reasons for missing a prayer and praying it qada'. But one shouldn't misinterpret these relaxations, as we today have alarm clocks etc. so we can do whatever is necessary to not miss a prayer, if nevertheless we missed it (after doing enough efforts not to do so) then and only then we can refer to this relaxation. A prayer time is a period of time that might take several hours so there should be enough time for praying a prayer during this period.
Also these five kids also should have a father who should help his wife or mother of his children.
As for going to Jahanamm first none of us can judge whether our good deeds will make us inhabitants of Jannah nor whether our bad deeds will lead us to Jahanamm, as the final judgement is by Allah. A good believer fears his Creator and hope for His forgiveness. And be aware that among the most severe sins a person could commit are those between humans as without the forgiveness of the opponent one may not be forgiven while Allah has the names ar-Rhamaan and ar-Raheem which both express extensive forgiveness and mercy.