83 year old with strange symptoms

[jbs30]

My 83 year-old  father is having aches and pains in his legs and arms and in his neck when he is bed and after waking up in the mornings and has to wait a few minutes on the end of the bed before standing up.  Three weeks ago he was diagnosed with anemia and given pills to increase his iron levels.
He will have a good day where there is little pain and then will have many days in a row where he has the aches in pains in his legs and arms that are affecting his daily life.  His General practitioner told him he just needs to let the iron pills work a little longer.  It's very frustrating and I am worried about my father.
Background: 3 weeks ago he was diagnosed with anemia and given pills to increase his iron levels.  He did have Covid in November 2020 and had the Moderna Vaccine in March of 2021.
Please help.

[Paxiled]

If he has anemia, he isn't eating very well or he isn't absorbing what he is eating very well.  He is also, let me be kind as I am no spring chicken, getting old, and stuff happens.  Also, some of those pills docs give out can't be absorbed by human beings very well, so he needs to be tested to make sure he is absorbing them.  Some form of iron is just not very well absorbed but is really inexpensive to produce and so more profitable than using better absorbed forms of iron.  Doctors are usually clueless about nutrition.