1 - My 1st question is about his pension
2 - 2nd Question is about Maryland Taxes
3 -Lastly, he's found H&R Block have a UK office and its on an air force base.
1 - Both may be right. For tax purposes, the treatment of a Government pension is different to the treatment of a personal pension (a 401k or whatever). It would depend on which pension the respective agency thought they were commenting on, and for which country.
2 - Six or seven States are difficult to break ties with. Some States break sensibly, and others hold to the principle that if you don't live there, you aren't a resident. I don't know where Md stands, but I would suggest you go to the Md web site and search for 'residence' or 'foreign resident' to see what you can find. On some sites, it's easy to find; on others, you may have to spend some time searching. Your partner will certainly need to file for their last year of residence.
3 - I know nothing about it.
Most on this site file a Form 2555, and their tax returns can be fairly easy. Once pension income enters the picture, it becomes much more difficult (and you can not use 2555 for pension income). As a result, if you wish to investigate this on your own, you will need to spend a fair bit of time doing the research. If you are not comfortable with that option, then (as Guya suggests) it would be best to contact a professional who has knowledge (and qualifications) in both countries.