As far as I know, you cannot change this as soon as you download the font. You can create a new Typeface from an existing font, for example:
Typeface typeface = Typeface.createFromAsset(getAssets(), "myfontfamily.otf");
Typeface boldTypeface = Typeface.create(typeface, Typeface.BOLD);
, , . (?) , , Bitstream Vera Sans Vera.ttf, VeraBd.ttf, VeraIt.ttf, VeraBI.ttf, /. Typeface , .
EDIT: , , , . - (, Photoshop Office ), TextPaint FAKE_BOLD_TEXT_FLAG, . , . , , , , .:)
, , , .